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s 

Bulletin  263  December,  1924  l  — ^ 

(^unmttuvd  A^rtrultural  ^^xpttmrnt  ^tatuin 

H^m  Manrn,  Qlonnrrtirut 


SECOND  REPORT 


OF   THE 


TREE  PROTECTION  EXAMINING  BOARD 


W.  E.  Britton,  Entomologist 
G.  P.  Clinton,  Botanist 
W.  O.  FiLLEY,  Forester 


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  of  Connecticut 
who  apply  for  them,  and  to  other  applicants  as  far  as  the  editions  permit. 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION 

OFFICERS  AND  STAFF 
December,  1924. 


BOARD  OF  CONTROL. 
His  Excellency,  Charles  A.  Templeton,  ex-offido,  President. 

George  A.  Hopson,  Secretary Mount  Carmel 

Wm.  L.  Slate,  Jr.,  Director  and  Treasurer New  Haven 

Joseph  W.  Alsop Avon 

Charles  R.  Treat Orange 

"Elijah  Rogers Southington 

Edward  C.  Schneider Middletown 

Francis  F.  Lincoln Cheshire 


STAFF. 
E.  H.  Jenkins,  Ph.D.,  Director  Emeritus. 

Wm.  L.  Slate,  Jr.,  B.Sc,  Director  and  Treasurer. 
Miss  L.  M.  Brautlecht,  Bookkeeper  and  Librarian. 
Miss  J.  V.  Bbrqer,  Stenographer  and  Bookkeeper. 
Miss  Mart  Bradley,  Secretary. 
William  Vbitch,  In  Charge  of  Buildings  and  Grounds. 

E.  M.  Bailey,  Ph.D.,  Chemist  in  Charge. 
R.  E.  Andrew,  M.A.  ] 

Owen  L.  Nolan  |     Assistant  Chemists. 

Harry  J.  Fisher,  A.B.      J 

Frank  C.  Sheldon,  Laboratory  Assistant. 

V.  L.  Churchill,  Sampling  Agent.  " 

Miss  Mabel  Bacon,  Stenographer. 

T.  B.  Osborne,  Ph.D.,  Sc.D.,  Chemist  in  Charge. 


Administration. 


Chemistry: 
Analj^ical 
Laboratory. 


Biochemical 
Laboratory. 

Botany. 


Entomology. 


Forestry. 

Plant  Breeding. 
Soil  Research. 


G.  P.  Clinton,  Sc.D.,  Botanist  in  Charge. 

E.  M.  Stoddard,  B.S.,  Pomologist. 

Miss  Florence  A.  McCormick,  Ph.D.,  Pathologist. 

Willis  R.  Hunt,  M.S.,  Graduate  Assistant. 

G.  E.  Graham,  General  Assistant. 

Mrs.  W.  W.  Kelsey,  Secretary. 

W.  E.  Bbitton,  Ps.D., Entomologist  in  Charge;  State  Entomologist 

B.  H.  Walden,  B.Agr.      1 

M.  p.  Zappe,  B.S.  >     Assistant  Entomologists. 

Philip  Garman,  Ph.D.      J 

Roger  B.  Friend,  B.Sc,  Graduate  Assistant. 

John  T.  Ashworth,  Deputy  in  Charge  of  Gipsy  Moth  Work. 

R.  C.  BoTSFORD,  Deputy  in  Charge  of  Mosquito  Elimination. 

Miss  Gladys  M.  Finley,  Stenographer. 

Walter  O.  Fillet,  Forester  in  Charge. 
A.  E.  Moss,  M.F.,  Assistant  Forester. 
H.  W.  HicocK,  M.F.,  Assistant  Forester. 
Miss  Pauline  A.  Merchant,  Stenographer. 

Donald  F.  Jones,  S.D.,  Geneticist  in  Charge. 
P.  C.  Mangelsdorf,  M.S.,  Graduate  Assistant. 

M.  F.  Morgan,  M.S.,  Investigator- 


Tobacco   Sub-station    N.  T.  Nelson,  Ph.D.,  Plant  Physiologist. 

at  Windsor. 


Th?  Wilson  H.  Lbb  Co. 


ANNOUNCEMENT. 

The  Tree  Protection  Examining  Board  created  by  the  General 
Assembly  of  1919  (see  PubHc  Acts  of  1919,  Chapter  181),  has 
adopted  this  as  its  Second  Report. 

ILLUSTRATIONS. 

The  illustrations  in  this  report  are  from  photographs  from  the 
following  sources:  Plate  XV,  a,  by  Mr.  Harry  B.  Kirk;  Plates  IX, 
X,  b,  XI,  a,  and  XIV,  d,  by  Mr.  B.  H.  Walden;  Plates  X,  a,  XI, 
c  and  d,  XIV,  a,  XIV,  d,  and  XVI,  by  Mr.  W.  0.  Filley;  Plates 
XII,  XIII,  XIV,  b  and  c,  XV,  b  and  c,  by  Dr.  W.  E.  Britton. 

W.  E.  Britton,  Entomologist, 

Chairman. 

G.  P.  Clinton,  Botanist, 

Vice  Chairman. 

W.  0.  Filley,  Forester, 

Secretary-Treasurer. 


CONTENTS. 

Page 

Second  Report  of  the  Tree  Protection  Examining  Board 141 

An  Act  Concerning  the  Improvement,  Protection  or  Preserva- 
tion of  Fruit,  Shade  or  Ornamental  Trees 141 

Examination  Rules  and  Regulations 142 

Renewal  of  Certificates 143 

Number  of  Certificates  Issued 143 

Firms  and  Individuals  Holding  Certificates. 144 

Examinations 147 

Form  of  Certificates 148 

Institutes  for  Instruction 150 

Financial  Statements 151 

Tree  Surgery 153 

Cavity  Work 154 

Some  of  the  Principal  Insects  Attacking  Shade  Trees  in  Connecticut.  156 

What  Insects  Are 156 

Common  Insecticides 157 

Leaf  Chewing  Insects 158 

Borers  or  Wood  Chewing  Insects ~. 163 

Sucking  Insects 167 

Fungous  and  Non-Infectious  Troubles  of  Ornamental  Trees 171 

Non-Infectious  Troubles 171 

Fungous  Diseases 181 

Leaf  and  Bark  Fungi \ 182 

Wood  Destroying  Fungi 190 


SECOND  REPORT 

OF  THE 

Tree  Protection  Examining  Board 

Coverins:  the  Three  Years  Ending  June  30,  1924 


The  first  report  of  the  Tree  Protection  Examining  Board  was 
issued  in  1921  as  Bulletin  231,  and  was  included  in  the  Annual 
Report  of  the  Station  for  that  year,  pages  339-350.  It  contained 
an  account  of  the  activities  of  the  Board  including  the  law,  rules 
and  regulations,  sample  examination  questions,  forms  of  certifi- 
cates, institute  program,  financial  statement,  list  of  firms  and 
individuals  receiving  certificates,  and  a  general  discussion  explain- 
ing the  reasons  for  legislation,  and  warning  tree  owners  to  employ 
qualified  men  for  their  tree  work  and  promising  to  investigate 
complaints. 

The  Station  is  often  asked  who  is  qualified  for  this  work,  and 
since  no  list  had  been  printed  since  1921,  a  revised  list  was  pub- 
lished, April  25,  1924,  as  Bulletin  of  Immediate  Information,  No. 
35,  entitled,  "Tree  Workers  Holding  Connecticut  Certificates." 
As  this  leaflet  does  not  contain  any  account  of  the  other  activities 
of  the  Board,  the  present  report  has  been  made  complete  for  the 
period  which  it  covers.  Sections  on  tree  surgery  and  on  the 
common  insect  and  fungous  pests  of  shade  trees  have  also  been 
added  as  a  source  of  information  to  tree  workers  and  tree  owners. 

The  members  of  the  Board  feel  that  the  legislation  on  this  sub- 
ject enacted  in  Connecticut  in  1919,  was  fully  justified  by  the 
conditions  then  existing,  and  believe  that,  on  account  of  this 
legislation,  these  conditions  have  since  greatly  improved.  More- 
over, the  Board  has  received  from  several  other  States  requests 
for  copies  of  the  Connecticut  law,  regulations,  and  examination 
and  certificate  forms,  with  the  statement  that  similar  legislation 
was  contemplated  in  those  states.  The  law  and  regulations  fol- 
low: 

AN   ACT   CONCERNING   THE   IMPROVEMENT,   PROTECTION 

OR  PRESERVATION  OF  FRUIT,  SHADE 

OR  ORNAMENTAL  TREES. 

Chapter  181.     Public  Acts  of  1919.     (In  effect  July  1,  1919.) 

Section  1.  No  person,  firm  or  corporation  shall  advertise,  solicit  or 
contract  to  improve  the  condition  of  fruit,  shade,  forest  or  ornamental 
trees,  by  pruning,  trimming  or  filling  cavities,  or  to  protect  such  trees  from 
damage  by  insects  or  disease,  either  by  spraying  or  any  other  method,  with- 
out having  secured  a  certificate  as  specified  in  section  two  of  this  act;  and 


142  CONNECTICUT   EXPERIMENT    STATION  BULLETIN   263. 

any  person,  firm  or  corporation  failing  to  comply  with  the  terms  of  this 
act  shall  be  fined  not  more  than  one  hundred  dollars;  provided  any  person 
may  improve  or  protect  any  tree  on  his  own  premises  or  on  the  property 
of  his  employer  or  on  any  property  within  the  limits  of  the  town  of  which 
he  is  a  legal  resident,  without  securing  such  a  certificate. 

Section  2.  The  botanist,  entomologist  and  forester  of  the  Connecticut 
Agricultural  Experiment  Station  shall  constitute  a  board  which  shall, 
upon  application  from  any  person,  firm  or  corporation,  examine  the  quali- 
fications of  the  applicant  to  improve,  protect  or  preserve  fruit,  shade, 
ornamental  or  forest  trees,  and  if  satisfied  that  the  applicant  is  qualified, 
may  issue  a  certificate  so  stating;  which  certificate  shall  be  valid  for  one 
year  from  the  date  of  its  issue,  unless  sooner  revoked  as  provided  in  section 
three  of  this  act,  and  may  be  renewed  by  the  board  for  succeeding  years 
without  further  examination,  upon  payment  of  the  fee  hereinafter  required, 
provided  any  person,  firm  or  corporation  receiving  such  certificate  shall  be 
responsible  for  the  acts  of  all  employees  in  the  performance  of  such  work. 

Section  3.  Said  board  shall  prepare  all  necessary  forms  and  prescribe 
all  rules  and  regulations  governing  examinations,  and  any  certificate 
issued  under  the  provisions  of  this  act  may  be  revoked  by  it  upon  proof 
that  improper  methods  have  been  used  or  for  other  sufficient  cause. 

Section  4.  Each  applicant  for  an  examination  shall  pay  a  fee  of  five 
dollars  in  advance,  and  a  fee  of  two  dollars  for  each  certificate  or  renewal 
issued;  which  fees  may  be  expended  by  the  board  for  any  expense  incurred 
by  it  in  making  examinations  or  issuing  certificates,  and  an  account  of  all 
receipts  and  expenditures  under  this  act  shall  be  rendered  annually  to  the 
state  comptroller. 

As  the  law  provides  that  this  Board  shall  consist  of  the  botanist, 
entomologist  and  forester  of  the  Station,  the  Board  was  organ- 
ized by  electing  as  Chairman,  W.  E.  Britton,  Entomologist,  as 
Vice-Chairman,  G.  P.  Clinton,  Botanist,  and  as  Secretary-Treas- 
urer, W.  O-  Filley,  Forester.  The  following  rules  and  regulations 
have  since  been  adopted  by  the  Board : 

Examination  Rules  and  Regulations. 

I.  Each  person,  firm  or  corporation  required  to  secure  a  certificate 
under  Chapter  181,  Public  Acts  of  1919,  shall  be  .examined  as  follows: 
When  a  firm  is  under  control  of  one  person  who  is  solely  responsible  for 
the  contracts,  methods  and  oversight  of  each  piece  of  work,  this  person 
alone  may  be  required  to  pass  the  examination,  but  when  more  than  one 
person  is  responsible  for  the  methods  of  work  and  oversight  of  same,  each 
shall  be  required  to  take  the  examination.  When  foremen  or  others  are 
given  complete  charge  of  recommending  and  applying  treatments,  they 
shall  also  be  required  to  take  the  examination,  in  so  far  as  it  relates  to 
their  work.  The  Examining  Board  shall  decide  who  shall  be  required  to 
take  the  examination. 

II.  Unless  otherwise  arranged,  candidates  for  certificates  shall  appear 
for  examination  at  the  Connecticut  Agricultural  Experiment  Station,  at 
New  Haven,  at  such  times  as  shall  be  designated  by  the  Board. 

III.  Examinations  may  be  oral,  written,  or  both,  as  shall  be  deter- 
mined by  the  Examining  Board,  and,  in  general,  shall  cover  tree  species, 
tree  life  and  growth;  diseases  and  insect  pests  of  trees,  with  treatment  for 
same;  pruning  and  tree  surgery. 

IV.  Candidates  prior  to  the  time  of  examination  shall  furnish  a  type- 
written statement  of  their  qualifications  as  follows: 


RENEWAL   OF    CERTIFICATES  143 

1.  General  education. 

2.  Special  training  for  tree  protection  work. 

3.  Experience  in  tree  protection  work.     The  latter  shall  include 

(a)  Place  of  business,  name  of  firm  and  position  now  held. 

(b)  Previous  positions  held. 

(c)  Total  length  of  experience. 

(d)  Contracts  now  under  way  or  completed  during  the  past  12 

months. 

In  addition  three  or  more  recommendations  as  to  reliability  and  effi- 
ciency shall  be  furnished;  and  where  typed  or  printed  forms  of  contracts, 
regulations,  etc.,  are  used,  these  shall  also  be  supplied,  or  if  not  available, 
statements  shall  be  made  concerning  the  same. 

V.  If  satisfied  with  the  qualifications  of  the  applicant,  the  Board  will 
issue  a  certificate  good  for  the  succeeding  twelve  months  (unless  revoked 
for  cause),  then  to  be  renewed  upon  application  under  such  conditions  as 
the  Examining  Board  may  require  in  each  case. 

VI.  Upon  evidence  of  unfitness  in  training  or  improper  business 
methods,  the  Examining  Board  may  refuse  to  issue  a  certificate  or  cancel 
one  that  has  been  issued.  Complaints  rnay  be  made  to  the  Board  on 
these  points,  and  if  deemed  desirable  by  the  Board,  private  hearings  of 
the  interested  parties  shall  be  held. 

Renewal  of  Certificates. 

The  provision  of  Section  4,  Chapter  181,  Public  Acts  of  1919,  regarding 
renewal  of  certificates  shall  be  construed  by  this  Board  as  meaning  a 
continuous  possession  of  a  certificate  and  not  an  attempt  to  obtain  a  new 
certificate  after  a  long  period  during  which  the  old  certificate  has  lapsed. 
The  following  rules  are  hereby  adopted: 

1.  The  secretary  shall  notify  each  certificate  holder  at  least  two  weeks 
before  his  certificate  expires,  and  again  two  weeks  after  date  of  expiration, 
unless  previously  renewed.  If  a  certificate  has  not  been  renewed  one 
month  after  date  of  expiration  it  then  becomes  invalid  and  the  holder 
shall  be  notified  to  that  effect. 

2.  An  invalid  certificate  may  be  revalidated  at  the  discretion  of  the 
Board  for  the  full  renewal  period  or  the  unexpired  portion  thereof,  if 
request  for  such  action  is  received  within  three  years  from  expiration  date 
and  if  all  renewal  fees  for  the  intervening  period,  as  well  as  the  renewal 
period,  are  paid  in  full. 

3.  If  application  is  made  on  or  before  the  expiration  date  of  a  certifi- 
cate, a  demit  or  respite  covering  a  period  of  three  years  may  be  issued 
without  charge,  entitling  the  holder  to  obtain  a  renewal  certificate  for  one 
year  on  payment  of  the  statutory  fee  of  $2.00. 

4.  If  after  three  years  with  or  without  a  demit  a  certificate  has  not 
been  renewed,  a  new  application  with  a  fee  of  $5.00  shall  be  necessary  and 
another  examination  may  be  required  by  the  Board. 

Number  op  Certificates  Issued 

In  all,  109  certificates  have  been  issued  by  the  Board  since 
the  law  became  effective.  Of  this  number,  80  are  now  in  force 
and  29  have  been  canceled ;  three  by  death,  four  by  changes  in 
business,  nine  by  removal  from  the  state  and  13  were  not  renewed. 
The  following  list  contains  the  names  of  individuals  and  firms 
now  holding:  certificates  which  are  in  force : 


144  CONNECTICUT    EXPERIMENT    STATION 

Firms  and  Individuals  Holding  Certificates 

Name  Address 

Armstrong  Tree  Service,  Ltd. 

Armstrong,  Newton  G Poughkeepsie,  N.  Y. 

Parmelee,  Leland  E Poughkeepsie,  N.  Y. 

Baldwin,  Thos.  J P.  O.  Box  176,  Guil- 
ford, Conn 

Bartlett  Tree  Expert  Co.,  F.  A. 

(F.  A.  Bartlett) Stamford,  Conn. .  .  . 

*Barton,  Robert P.  O,  Box  57,  Ham- 
den,  Conn 

Beaupain  &  Saunders 

(Henry  F.  Beaupain) So.  Norwalk,  Conn. 

*Bertolf  Brothers 

(August  C.  Bertolf ) . Sound  Beach,  Conn. 

Brown,  Edgar  M  .  .  .  . '. 211    Sisson    Ave., .  . 

Hartford,  Conn... 

Calverley,  Arthur 763  Campbell  Ave., 

West  Haven,  Conn. 

Cardarelli,  Emilio  J Cromwell,  Conn. . .  . 

Clark,  Harry  E Middlebury,  Conn. . 

Clark,  Wyllis  S New  Canaan,  Conn. 

Clyne,  G.  A 73  Canal  St.,  Water- 
bury,  Conn 

Condon  Co.,  Maurice  L. 

(Maurice  L.  Condon) Lake  Mahopac,  N.Y. 

Cromie,  George  A 18    Compton    St., 

New  Haven, Conn. 
Davey  Tree  Expert  Company  Kent,  Ohio. 

Baldwin,  H.  E General       Delivery, 

Norwich,  Conn. .  . 
Gammie,  Peter P.O.  Box  423,  Stam- 
ford, Conn 

Grove,  D.  Q Kent,  Ohio 

Landis,  Ray  E 28  Smith  St.,   Dan- 
bury,  Conn 

Liming,  O.  N General       Delivery, 

Stonington,  Conn. 

Tuomey,  W.  W General       Delivery, 

South      Manchester, 

Conn 109 

f  Desmond,  Thomas  H Simsbury,  Conn.  .  .  . 

DeWolfe,  John  C.  G 85     Medford    St., 

Medford,  Mass. .  . 

Dunham,  L.  N 45      Park      Terrace, 

New  Britain, Conn. 

Easton,  Clifford  H P.    O.    Box    No.    1, 

Scarborough,  N.Y. 
*Elm  City  Nursery  Co., 

J.  L.  Donnelly Box     15  8  8,     New 

Haven,  Conn .... 

*Ernst,  Otto  F Norwich,  Conn 

Fertsch,  Ross  L P.  O.  Box  220,  New- 
burgh,  N.  Y 

Galligan,  Clarence  W 15    Admiral    Street, 

Allingtown,  Conn. 


BULLETIN 

263. 

riFICATES 

Cert. 
No. 

Certificate 
Expires 

86 

89 

May  25, 
July  23, 

1925 
1925 

21 

July  15, 

1925 

10 

July   15, 

1925 

66 

Dec.  18, 

1924 

27 

Aug.  12, 

1925 

24 

July  29, 

1925 

52 

June    6, 

1925 

97 
57 
72 
20 

Mar.  31, 
Feb.  28, 
Mar.    8, 
July   15, 

1925 
1925 
1925 
1925 

5 

July    1, 

1925 

46 

Feb.     2, 

1925 

88 

May  25, 

1925 

91 

July  23, 

1925 

60 

87 

May  26, 
May  25, 

1925 
1925 

108 

May  15, 

1925 

102 

'  May    8, 

1925 

109 
50 

June  15, 
April    4, 

1925 
1925 

80 

Aug.     7, 

1925 

104 

May    8, 

1925 

53 

June  16, 

1925 

105 
79 

May  12, 
July  14, 

1925 
1925 

84 

April    4, 

1925 

74 

June  28, 

1925 

*  Is  also  a  nurseryman. 

t  Is  also  a  landscape  architect. 


LIST    OF    CERTIFICATE    HOLDERS  145 

Firms  and  Individuals  Holding  Certificates — Continued 

Name  Address 

Gibbs,  R.  M 33    Fairfield    Street, 

Pittsfield,  Mass. . . 

Gilbert,  J.  E 376    George    Street, 

New  Haven, Conn. 
fGoodwin  Associates,  James  L., 

James  L.  Goodwin 750  Main  St.,  Hart- 
ford, Conn 

Graf,'  Albert  H P.   O.   Box  87,  Bar- 

donia,  N.  Y 

Grovit,  Albert 986    Whalley    Ave., 

New  Haven,  Conn. 
Gustafson,  Harry  A P.  O.  Box  81,  Water- 
town,  Conn 

Hartford  Forestry  Company 

Hansling,  Philip,  Sr 65    Sherman    Street, 

Hansling,  Philip,  Jr Hartford,  Conn..  . 

Herthal,  G.  F 228   Bunnell   Street, 

Bridgeport,  Conn. 

Herthal,  Gus.,  Jr 228    Bunnell    St., .  . 

Bridgeport,  Conn. 

HoUister,  S.  P Conn.   Agr.   College, 

Storrs,  Conn 

Horlacher,  John  J 197  Thomas  Street, 

West  Haven,  Conn. 

*Hunt  &  Co.,  W.  W.,  167  Blue  Hills  Ave., 

(W.  A.  Wright)  Hartford,  Conn. . 

Kellner,  Arthur  H 7   Grove   St.,    South 

Norwalk,  Conn. . . 

*Kellner,  Herman  H Danbury,  Conn .... 

*Kelley,  James  J New  Canaan,  Conn. 

Landscape  Foresters,  Ltd.        52  Vanderbilt  Ave., 
(C.  E.  Mager)  New  York  Citv  .  . 

*tMallett  Co.,  G.  A., 95      Catherine     St., 

(George  A.  Mallett)  Bridgeport,  Conn. 

Maynard,  Eugene 61  Coit   St.,    New 

London,  Conn.. .  . 
McLaughlin  &  Carberry 

Carberr^^  Joseph  V Sharon,  Conn 

McLaughlin,  J.  A Sharon,  Conn *  77 

Meader  Co.,  L.  H 75  Westminster  St., 

(Lewis  H.  Meader)  Providence,  R.  I.. .  . 

*Millane  Tree  Expert  Co., 

(Neal  A.  Millane) Middletown,  Conn. . 

Morris,  Harry  H 9    Winthrop    Place, 

Danbury,  Conn .  . 

Munson-Whitaker  Co 1     Washington     St., 

(Robert  O'Shea).  Boston,  Mass.  .  .  . 

Murphy,  Allen  L Bethel,  Conn 

Old  Colony  Forestry  Co 415  Savin  Ave., 

(Thomas  J.  McGinnis)  West  Haven, Conn, 

O'Gara,  Charles  E 696     Dixwell  Ave., 

New  Haven,  Conn. 
Pauley  Tree  Expert  Co., 

(George  A.  Pauley)  New  Canaan,  Conn. 


Cert 
No. 

Certificate 
Expires 

83 

April    4,  1925 

61 

May  26,  1925 

39 

Nov.  26,  1925 

67 

Dec.  18,  1924 

85 

April    6,  1925 

96 

Mar.  25,  1925 

17 
16 

July   15,  1925 
July  15,  1925 

25 

July  29,  1925 

36 

Sept.  17,  1925 

47 

Mar.  21,  1925 

103 

May    8,  1925 

33 

Sept.  17,  1925 

26 

101 

19 

Aug.  12,  1925 
April    1,  1925 
July   15,  1925 

32 

Sept.  17,  1925 

11 

July   15,  1925 

94 

Feb.     6,  1925 

78 
•  77 

July     9,  1925 
July     9,  1925 

31 

Sept.  17,  1925 

1 

July     1, 1925 

40 

Nov.    6,  1925 

42 
106 

Nov.  25,  1925 
May  15,  1925 

4 

July     1,  1925 

110 

Aug.  28,  1925 

22 

July  29,  1925 

*  Is  also  a  nurseryman. 

t  Is  also  a  landscape  architect. 


146  CONNECTICUT    EXPERIMENT    STATION  BULLETIN    263. 

Firms  and  Individuals  Holding  Certificates — Concluded 

Cert.  Certificate 

Name  Address  No.  Expires 

Perry,  Lewis Southington,  Conn. .        95       Feb.     6,  1925 

Plumb,  C.  K.  &  J.  C. 

(C.  K.  Plumb)     New  Canaan,  Conn.      100       Mar.  31,  1925 

Pool,  William  H 47     Sheffield     Ave., 

Roslindale,  Mass.        63       Oct.    10,  1925 
Rice,  Ralph  S 71   Howard  Avenue, 

New  Haven,  Conn.       69       Dec.  18,  1924 
Rich,  Nehemiah  L 101    Warren    Street, 

Stamford,   Conn.  3        July      1,  1925 

*Rockfall  Nursery  Co., 

(Philip  Marotta) Rockfall,  Conn 71       Mar.    8,  1925 

Rottenberg,  Julius Newington  Gardens, 

Newington       Jet., 

Conn 93       Jan.      9,  1925 

Royal  Forestry  Co 124       Division     St., 

(Charles  Vallett)  Waterbury,  Conn. 

*Schoonman,  W.  J New  London,  Conn. 

Shaw,  Walter 494    Blake    St., 

Westville,  Conn.  . 
*Sierman,  C.  H 2291    Albany    Ave., 

West        Hartford, 

Conn 

*Steck:,  Harold  W Newtown,  Conn. .  .  . 

Szirbik,  George 77  East  Ramsdell  St., 

Westville,  Conn.  . 

*van  Heinigen,  Jacob  C South  Wilton,  Conn. 

van  Kleef ,  Marinus Bridgewater,  Conn. . 

*Van  Wilgen  Company 

Van  Wilgen,  A.  C 71  Main  St., 

Van  Wilgen,  W.  C Branford,  Conn.  . 

*Verkade,  H Corner    Crocker    St. 

and  Lower  Boule- 
vard, New  London, 

Conn 

Wilcox,  Reginald  C Essex,  Conn 

Wright,  John  L P.  O.  Box  593,  Put- 
nam, Conn 43       Nov.  25,  1925 


62 
6 

Aug. 
July 

5, 
1, 

1925 
1925 

55 

June 

16, 

1925 

8 
92 

July 
Jan. 

1, 
10, 

1925 
1925 

.11 

48 

75 

Aug. 
April 
July 

28, 
4, 
4, 

1925 
1925 
1925 

99 

98 

Mar. 
Mar. 

31, 
31, 

1925 
1925 

18 
30 

July 
Sept. 

15, 
17, 

1925 
1925 

*  Is  also  a  nurseryman. 


EXAMINATIONS  147 


Examinations 


The  law  provides  that  the  fee  of  $5.00  shall  be  paid  in  advance. 
The  form  of  application  now  in  use  is  as  follows : 


Tree  Protection  Examining  Board, 
Box  1106,  New  Haven,  Conn. 

Gentlemen : — 

I  hereby  apply  for  a  certificate  as  provided  in   Chapter  181, 
Public  Acts  of  1919,  to  be  issued  in  the  name  of 

Enclosed  is  examination  fee  of  $.5.00  required  by  law. 

Signature  of  Applicant 
Business  Address 


It  has  been  the  practice  of  the  Board  to  hold  an  examination 
only  when  there  were  enough  applicants  to  warrant  one,  rather 
than  to  set  a  special  date  for  each  applicant,  and  it  has  usually 
been  possible  to  examine  three  or  more  candidates  at  one  time. 
There  have  been  occasional  requests  for  examination  by  mail,  but 
as  a  matter  of  policy,  the  Board  has  insisted  on  candidates  appear- 
ing before  it  in  person. 

Since  the  last  report.  16  examinations  have  been  held  as  fol- 
lows : 

In  1921— July  26,  October  3,  December  19. 

In  1922— March  9,  May  18.  June  26,  October  27. 

In  1923 — \pril  2,  May  25,  Julv  23.  November  26. 

In  1924— February  5,  March  25,  May  2,  June  6,  August  28. 

Fifty-three  candidates  presented  themselves.  Of  this  number, 
48  were  granted  certificates  without  condition,  three  were 
requested  to  take  a  second  examination,  one  was  refused  a  certifi- 
cate, and  one  passed  the  examination  but  decided  he  did  not  need 
a  certificate.  Fifty-one  certificates  were  issued  during  the  period 
covered,  making  a  total  of  109  certificates  issued  during  the  first 
five  years  of  the  Board's  existence. 


148  connecticut  experiment  station          bulletin  263. 

Form  of  Certificates 

The  form  of  the  regular  certificate  adopted  and  used  by  the 
Board  is  as  follows : 

*  % 

1  CERTIFICATE  | 

9  FROM                                                                                                9 

9  9 

i  STATE  OF  CONNECTICUT                                         1 

9  9 

I  ^^                               I 

9  m 

9     X5\)is  Is  to  (tcrtify  ihat * 

*  ......         9 

9      of has  been  duly  examined  in  compliance  with  the  provisions      9 

9  9 

2  of  Chapter  181,  Public  Acts  of  1919,  and  is  considered  qualified  to  conduct  the  business  of  pro-      £ 

9  9 

£  tectmg  trees.                                                                                                                                               £ 

9  \               * 

9         No _  Enlomologisl.  Chairwan  \  9 

9  9 

*  Dat. Boi^i^.VlccChcinnan)^''"'^"'^        5 

9  i     Board            9 

9  '                                                                                                                                                                    \                         * 

a^        Ejcpires. .      _       _  ForeslCT.  Srcs-7rto5.      I  9 

9  '              9 

9  '                      CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION                                                    9 

9  9 

»  NEW  HAVEN.  CONNECTICUT                                                                                                       A 

9  9 


CERTIFICATE    FORMS  149 

At  the  expiration  of  the  regular  certificate,  if  the  fee  of  two 
dollars  ($2.00)  has  been  paid,  a  renewal  certificate  is  issued  in 
the  following  form: 

X5«CX;}CX3eCXXXXX!XSX5«XXXXXXXXXXXXX^ 

I  RENEWAL  CERTIFICATE  Jc 

X  FROM  X 

X  X 

I    ®r^0  PrntKttDtt  iExammmg  loari    x 


STATE  OF  CONNECTICUT 


X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 

2{       T^his  is  to  Certify  that  Certificate  No was  issued  by  this      x 

X  X 

V      Board  on to X 

X  X 

H      of ,  as  provided  by  Chapter  181,  Public      v; 

5      Acts  of  1919,  and  said  certificate  is  hereby  renewed  for  one  year      x 

X  r  X 

X      from X 

X       Renewal  Entotnologist,  Chairman      x 

X  X 

X      Expires Botanist,  Vice- Chairman      x 

X      Issued Forester,  Sec'y-  Treas.  x 

X  '  X 

X  Connecticut  Agricultural  Experiment  Station  X 

X  NEW    HAVEN,    CONNECTICUT  X 

X  X 

XXXXXXiXXiXjXKiXiXAKjrCXKirSiXKj?>i?^ 

To  show  that  men  are  working  under  a  valid  certificate 
issued  by  the  Board,  a  small  card  was  furnished  for  each  foreman 
employed  by  a  firm  or  an  individual.  The  form  of  this  card  is 
shown  below: 


^tatr  uf  (Cnnnprtirut 

TREE  PROTECTION  EXAMINING  BOARD 


THE    BEARER 

is  working  under  supervision  of  and  is  responsible  to 

of Conn., 

to  whom  this  board  has  issued  Certificate  No as  provided  by 

Chapter  181,  Public  Acts  of  1919.     Said  certificate  expires 

Connecticut  Agricultural 

Experiment  Station         

NEW   HAVEN,    CONN.  Secretary 


150  connecticut  experiment  station  bulletin  263. 

Institutes  for  Instruction 

The  early  examinations,  as  well  as  some  of  the  more  recent 
ones,  have  shown  that  many  of  the  tree  men  are  not  well  versed 
in  the  life  processes  and  care  of  trees.  Consequently,  early  in  the 
first  year  after  the  law  was  passed,  an  institute  of  instruction 
was  held  at  the  Station  at  which  the  various  phases  of  tree  life 
and  growth  were  discussed.  The  results  were  such  that  the 
Board  has,  in  each  of  the  years  1922,  1923  and  1924,  conducted 
a  one-day  institute  for  this  purpose,  in  some  cases  at  the  request 
of  the  tree  workers.  In  all,  four  institutes  have  been  held,  the 
program  of  the  first  being  given  in  the  first  Report  of  the  Board. 
The  attendance  has  A^aried  between  50  and  100,  and  deep  interest 
has  been  shown.  The  program  and  date  of  each  of  the  other 
institutes  are  given  below : 

February  21,   1922 

10.00  A.M.  The  Living  Tree  (Illustrated),  by  Dr.  George  E.  Nichols, 
Assistant  Professor  of  Botany  in  Yale  University,  New  Haven,  Conn.; 
The  Pruning  and  Spraying  of  Fruit  Trees,  by  Prof.  Sherman  P.  HoUister, 
Assistant  Professor  of  Pomology,  Connecticut  Agricultural  College, 
Storrs,  Conn. ;  Effects  of  Smoke,  Gases  and  Electricity  Upon  Trees,  by 
Prof.  J.  W.  Toumey,  Dean  School  of  Forestry,  Yale  University,  New 
Haven,  Conn.;  Observations  on  Oil  Injury  to  Trees,  by  Dr.  E.  P.  Felt, 
State  Entomologist,  Albany,  New  York.  12.00,  Recess  for  luncheon. 
1.30  P.  M.  Pruning  and  Cavity  Work  as  Applied  to  Shade  Trees  (Illu- 
strated), by  J.  Franklin  Collins,  Forest  Pathologist,  U.  S.  Dept.  of 
Agriculture,  Brown  University,  Providence,  R.I.;  Discussion,  led  by 
Dr.  George  E.  Stone,  Amherst,  Mass.;  Modern  Methods  of  Tree 
Surgery  (Demonstration),  by  F.  A.  Bartlett,  Bartlett  Tree  Expert 
Company,  Stamford,  Conn.;  Some  Common  Insect  Pests  of  Shade  Trees 
(Illustrated),  by  Dr.  E.  P.  Felt,  State  Entomologist,  Albany,  New  York; 
Report  on  work  of  Tree  Protection  Examining  Board,  by  W.  O.  Filley, 
Forester,  Connecticut  Agricultural  Experiment  Station,  New  Haven, 
Conn.;  Report  of  Committee  on  Organization  of  a  Tree  Protective  Asso- 
ciation in  Connecticut. 

March  1,  1923 

10.00  A.M.  Opening  Remarks,  by  Dr.  W.  E.  Britton,  State  Entomo- 
logist, New  Haven,  Conn.;  The  Tree  in  the  Landscape  (Illustrated),  by 
Ernest  F.  Coe,  Landscape  Architect,  New  Haven,  Conn.;  The  Gipsy 
Moth,  by  A.  F.  Burgess,  In  Charge  of  Moth  Work,  U.  S.  Bureau  of  Ento- 
mology, Melrose  Highlands,  Mass.;  Some  Insects  Attacking  Shade  Trees 
(Illustrated),  by  Dr.  E.  P.  Felt,  State  Entomologist,  Albany,  N.  Y. 
12.15  p.m.  Recess  for  luncheon.  2.00  p.m.  The  Living  Tree  (Illustrated), 
by  Dr.  G.  E.  Nichols,  Assistant  Professor  of  Botany,  Yale  University, 
New  Haven,  Conn.;  Wood  Rot  Fungi  (Illustrated),  by  Dr.  W.  A.  Murrill, 
New  York  Botanical  Garden,  New  York,  N.Y.;  Mechanical  Injuries 
and  Their  Treatment  (Illustrated),  by  Dr.  G.  E.  Stone,  Amherst,  Mass.; 
Fertilizers  for  Trees,  by  Dr.  E.  H.  Jenkins,  Director,  Connecticut  Agri- 
cultural Experiment  Station,  New  Haven,  Conn. 

March  11,  1924 

10. 00  a.m.  Opening  Remarks,  by  Dr.  W.  E.  Britton,  State  Entomo- 
logist, New  Haven,  Conn.;  Word  of  Welcome,  by  W.  L.  Slate,  Jr.,  Director, 
Connecticut  Agricultural  Experiment  Station,  New  Haven,  Conn.;  The 


FINANCIAL    STATEMENTS  151 

Living  Tree  (Illustrated),  by  Dr.  G.  E.  Nichols,  Assistant  Professor  of 
Botany,  Yale  University,  New  Haven,  Conn.;  Some  Fungous  Diseases 
of  Trees  (Illustrated),  by  Dr.  A.  H.  Graves,  Curator  of  Public  Instruc- 
tion, Brooklyn  Botanic  Garden,  Brooklyn,  N.Y.  12.15  p.m.  Recess 
for  Luncheon.  2.00  p.m.  Some  Insects  Attacking  Shade  Trees  (Illus- 
trated), by  Prof.  W.  C.  O'Kane,  Professor  of  Economic  Entomology, 
University  of  New  Hampshire,  Durham,  N.  H.;  Some  Insects  Requiring 
Special  Attention  the  Coming  Season  (Illustrated),  by  Dr.  W.  E.  Britton, 
State  Entomologist,  New  Haven,  Conn.;  Cavity  Work,  Pruning,  and 
Spraying  (Illustrated),  by  George  A.  Cromie,  Superintendent  of  Trees, 
New  Haven,  Conn. 

Financial  Statements 
treasurer's  account 

July  1,  1921— June  30,  1922 

Balance  on  hand  July  1,  1921 $213.98 

Received  for    18  examination  fees  @  $5.00 $90.00 

"      44  renewal  fees  @  $2.00 88.00  178.00 

$391.98 

Expended  for  Printing  and  Stationery $28.45 

"  "    Postage 18.36 

"  "    Travel  Expenses  of  Board 20.92 

"  "    Institute  Expenses 36.87 

"  "    Miscel.  office  expense 1.80  106.50 

$285.48 
Receipts  paid  Comptroller,  for  deposit  in  State 

Treasury 178.00 

Balance  on  hand  June  30,  1922 $107.48 

July  1,  1922— June  30,  1923 

Received  for    10  examination  fees  @,  $5.00 850.00 

"  "    52  renewal  fees  @,  $2.00 104.00  154.00 

S261.48 

Expended  for  Printing  and  Stationery $42.65 

"  "    Postage 6.00 

"  "    Institute  Expenses 49.29  97.94 

$163.54 

Receipts  paid  Comptroller,  for  deposit  in  State 

Treasury 154.00 

Balance  on  hand  June  30,  1924 $9.54 

July  1,  1923 — June  SO,  1924 

Received  for   21  examination  fees  @  $5.00 $105.00 

"  "    60  renewal  fees  @  $2.00 120.00  225.00 

$234.54 

Expended  for  Printing  and  Stationery $3.13 

"  "    Institute  Expenses 6.41  9.54 

$225.00 
Receipts  paid  Comptroller,  for  deposit  in  State 

Treasury 225.00 


152              CONNECTICUT   EXPERIMENT   STATION  BULLETIN   263. 

comptroller's  ACCOUNT 

Amounts  deposited  in  State  Treasury, 

July  1,  1921— June  30,  1922 $178.00 

July  1,  1922— June  30,  1923 154.00 

July  1,  1923— June  30,  1924 225.00 

$557.00 
Expenditures  by  Comptroller,  on  order  of  the  Board, 

For  Printing  and  Stationery $64.18 

Postage 16.00 

Travel  Expenses  of  Board. 7.75 

Institute  Expenses 43.52 

Miscellaneous  Office  Expense 11.98 

143.43 


Balance  available  in  State  Treasury,  June  30,  1924 $413.57 


TREE    SURGERY  153 

TREE  SURGERY 

W.  O.  PILLEY 

The  problems  confronting-  those  interested  in  the  protection 
and  care  of  ornamental  trees  are  many  and  various.  Some  prob- 
lems relating  to  foliage,  bark,  and  exposed  portions  of  the  trees 
are  simple  of  solution  and  results  of  treatment  are  readily 
observed.  In  some  cases,  as  in  spraying  with  chemicals,  com- 
plications may  arise  which  require  further  study,  but  even  in  such 
cases  the  parts  concerned  are  open  to  observation  and  the  methods 
used  are  susceptible  of  proof  by  observation  and  test. 

The  filling  of  cavities,  treatment  of  wounds,  stimulation  of 
growth  by  fertilization  and  cultivation  of  soils,  and  other  prob- 
lems which  involve  growth  and  condition  of  woody  tissues  are 
much  more  difficult  of  solution.  In  such  cases,  results  from 
applied  methods  are  not  easy  to  determine,  and  there  is  great 
divergence  of  opinion  regarding  the  efficiency  of  methods  which 
are  difficult  to  standardize.  This  fact  makes  it  possible,  and 
almost  inevitable,  that  secret  or  patented  processes  should  become 
the  basis  of  business  getting  rather  than  knowledge  and  skill. 

With  due  appreciation  of  this  situation  and  believing  that  the 
solution  of  many  of  these  problems  is  possible  through  concerted 
action  on  the  part  of  those  interested,  this  Board  invited  a  num- 
ber of  scientists,  tree  workers  and  officials  to  join  it  in  a  Shade 
Tree  Conference  at  Stamford,  Conn.,.  August  25-26.  1924.  This 
conference  (probably  the  first  of  its  kind  in  this  country)  was 
attended  by  36  individuals,  including  botanists,  entomologists 
and  practical  tree  workers.  The  definite  results  were  summed  up 
in  the  conclusions  of  Dr.  Haven  Metcalf,  Forest  Pathologist,  U. 
S.  Bureau  of  Plant  Industry. 

"Tree  surgery,"  he  stated,  "is  about  where  dentistry  was  in 
the  60's ;  its  first  object  being  looks.  We  believe  that  it  does  pro- 
long the  life  of  trees  but  we  cannot  prove  it,  and  there  is  almost 
no  literature  on  the  subject.  What  is  needed  more  than  any- 
thing else  is  research  records  and  case  histories." 

It  was  voted  that  another  conference  should  be  held  in  1925, 
of  which  Dr.  Haven  Metcalf  was  elected  chairman  and  W.  O. 
Filley,  secretary,  with  instructions  to  make  all  necessary  arrange- 
ments. 

It  may  be  truly  stated  that  nothing  new  came  out  of  this  con- 
ference. Everything  which  was  said  had  doubtless  been  said 
before.  Nevertheless,  the  meeting  served  its  purpose  in  bringing 
together  scientists  and  tree  workers  for  an  informal  discussion 
of  shade  tree  problems.  Future  conferences  will  undoubtedly 
show  more  definite  progress  toward  their  solution. 

The  feeling  of  many  regarding  the  uncertain  status  of  cavity 
work  was  expressed  in  a  short  paper  by  Dr.  Collins  of  the  U.  S. 


154  CONNECTICUT    EXPERIMENT    STATION  BULLETIN    263. 

Bureau  of  Plant  Industry.  He  has  consented  to  its  publication 
as  a  part  of  this  report. 

In  common  with  many  other  observers,  this  Board  has  felt  that 
the  importance  of  cavity  treatment  and  filling  was  somewhat 
over-emphasized,  as  compared  with  improvement  of  soil  condi- 
tions, proper  pruning-  and  treatment  of  wounds,  protection  from 
insect  and  fungous  pests,  etc.  Much  wonderfully  fine  workman- 
ship has  gone  into  the  filling  of  cavities,  and  in  many  cases  it 
may  have  lengthened  the  life  of  the  trees  concerned,  but  in  others 
it  has  only  served  to  increase  the  size  of  the  bill. 

Neverthless  cavity  work,  like  the  treatment  of  wounds,  brac- 
ing, and  other  forms  of  tree  repair,  is  demanded  by  tree  owners, 
w^ho  are  read}^  to  pay  for  expert  knowledge  and  skill.  In  return, 
they  have  a  right  to  expect  definite  results,  which  can  only  be 
assured  through  standardized  methods  applied  with  judgment 
and  honest  intent.  Tree  workers  ought  to  be  able  to  say  that  a 
certain  method  is  the  right  one  because  it  has  stood  the  test  of 
time  and  is  so  universally  used  that  it  has  become  standardized. 
This  can  only  come  about  through  careful  observation  of  results, 
frequent  exchange  of  ideas  with  other  tree  workers  and  close 
co-operation  with  scientific  workers  who  are  keenly  interested 
in  the  solution  of  these  problems. 

CAVITY  WORK 

J.  FRANKLIN  COLLINS 
(Read  before  the  Shade  Tree  Conference,  Stamford,  Conn.,  Aug.  25,  1924) 

Before  speaking  of  cavity  work  I  wish  to  correct  an  erroneous 
impression  that  seems  to  be  somewhat  prevalent  regarding  the 
scope  of  the  tree  repair  work  being  done  by  our  Washington 
office.  The  Bureau  of  Plant  Industry  is  not  primarily  concerned 
with  the  work  of  commercial  "tree  surgeons,"  nor  has  it  ever 
been,  so  far  as  I  know.  Its  primary  interest  lies  in  tr3dng  to  help 
the  man  who  owns  a  few  trees  (either  shade,  ornamental  or 
orchard)  to  keep  them  in  good  condition  so  far  as  disease  and 
mechanical  injury  is  concerned,  or  to  advise  him  how  best  to 
repair  fresh  injuries,  as  well  as  neglected  ones  that  may  have 
occurred  in  the  past.  To  put  the  matter  in  another  way,  we  are 
concerned  primarily  wuth  the  question,  "What  is  the  best  advice 
to  give  to  a  man  who  has  a  few  trees  that  he  wants  to  care  for  him- 
self and  who  would  never,  for  financial  or  other  reasons,  employ 
a  commercial  tree  surgeon  to  attend  to  them  ?"  That  is  the  infor- 
mation that  we  have  tried  to  give  in  Farmers'  Bulletin  1178,  and 
the  first  paragraph  in  this  Bulletin  expressly  states  this  to  be  its 
object.     I  might  also  add,  this  is  its  sole  object. 

I  think  it  is  the  general  opinion  of  the  majority  of  tree  workers 
that  preventing  decay  is  far  better,  from  all  points  of  view,  than 


CAVITY    WORK  155 

tr3-ing-  to  cure  it.  I  think  nearly  all  tree  workers  (certainly  all 
scientific  workers)  also  will  agree  that  a  decayed  spot  in  a  trunk 
or  a  large  limb  should  be  carefully  cleaned  out,  sterilized,  and 
treated  in  such  a  manner  as  to  prevent,  so  far  as  possible,  any 
reinfection. 

Beyond  this  point  there  obviously  is  a  difference  of  opinion 
even  among  commercial  tree  surgeons,  as  to  what  is  the  best 
thing  to  do  with  the  cleaned  out  cavity :  i.e.,  whether  to  leave  it 
open,  to  cover  it  with  sheet  metal,  or  to  fill  it  with  concrete  or 
asphalt  mixtures,  wood,  or  other  materials. 

For  the  past  15  3'ears  when  traveling  about  the  countr}-,  pri- 
marily on  other  business,  I  have  made  it  a  point  to  look  over 
cement-filled  cavities  wherever  I  have  been  and  had  the  time  to 
do  so,  and  check  up  on  their  general  condition.  My  method  of 
checking"  was  to  count  only  fillings  that  had  been  in  place  for  a 
few  years  so  as  to  get  some  idea  of  their  permanency.  Those 
which  showed  obvious  cracks,  chipped  cement,  severe  dying  back 
of  the  cambium,  excessive  leakage,  or  a  loose  filling  were  con- 
sidered defective.  Judged  on  this  basis  more  than  90  per  cent, 
of  all  the  fillings  examined  have  proved  to  be  defective.  I  was  not 
particularl}-  concerned  with  who  did  the  work,  although  in  some 
cases  I  was  told  who  did  it.  Undoubtedly  most  of  this  work  had 
been  done  by  men  trained,  at  least  to  some  extent,  in  the  work, 
as  the  trees  examined  were  located  primarily  along  streets  or  on 
large  estates  where  commercial  men  had  been  employed  to  do  it. 

1  have  had  opportunity  to  dig  out  quite  a  number  of  fillings 
that  had  been  in  place  for  periods  varying-  from  eight  to  15  years, 
and  most  of  these,  even  when  absolutely  perfect  on  the  surface, 
were  found  to  be  badly  decayed  back  of  the  cement,  in  some  cases 
the  decayed  area  back  of  the  cement  was  larger  than  the  original 
cement-filled  cavity  itself.  As  a  result  of  such  observations  as 
these  it  is  hardly  to  be  expected  that  the  use  of  cement  in  other 
than  small  and  globular  cavities  could  conscientiously  be  recom- 
mended for  the  use  of  untrained  persons,  to  say  the  least. 

So  far  as  asphalt  mixtures  or  wood  strips  and  blocks  are  con- 
cerned I  can  only  say  that  although  they  appear  to  me  to  give 
promise  of  good  results  after  they  have  been  in  practical  use  long 
enough  to  know  just  how  they  can  best  be  handled,  they  have  not 
yet  stood  the  test  sufficiently  long  to  demonstrate  satisfactorily 
to  me  their  real  value  and  limitations.  Consequently,  thev  are  not 
at  present  recommended  by  us  for  the  use  of  untrained  men, 
except  on  an  experimental  basis. 


156  CONNECTICUT    EXPERIMENT    STATION  BULLETIN    263. 

SOME    OF    THE    PRINCIPAL    INSECTS    ATTACKING 
SHADE  TREES  IN  CONNECTICUT 

W.    E.   BRITTON 

It  is  often  necessary  to  spray  shade  trees  in  Connecticut  in 
order  to  control  certain  insects  which  otherwise  might  seriously 
injure  the  trees.  In  summer  there  are  various  chewing  insects 
which  devour  the  foliage,  and  there  are  also  other  insects,  such 
as  aphids  and  scales,  which,  when  abundant,  make  a  heavy  drain 
upon  the  trees  by  sucking  out  the  sap.  Though  most  of  these 
pests  do  not  kill  the  trees  in  a  single  season,  yet  they  weaken  them, 
and  if  a  tree  is  completely  defoliated  two  or  three  times  in  suc- 
cession, death  may  result. 

In  cities  and  towns  as  well  as  on  large  estates  and  other  private 
holdings  where  the  trees  are  an  important  asset,  every  effort 
should  be  put  forth  to  keep  the  trees  in  the  best  possible  health 
and  vigor.  Such  a  program  must  include  provision  for  spraying 
the  trees  to  rid  them  of  their  insect  pests.  Perhaps  it  may  not  be 
necessary  to  treat  them  every  season  because  these  pests  fluctuate 
in  abundance  from  year  to  year,  and  when  absent,  it  might  be 
wasting  money  to  spray  the  trees.  But  the  trees  should  be 
watched,  and  materials  and  apparatus  should  be  always  at  hand 
in  readiness  to  make  the  application  whenever  the  conditions  seem 
to  warrant  it.  In  no  other  way  can  the  trees  be  given  the  most 
intelligent  care. 

What  Insects  Are 

Insects  are  small  animals  belonging  to  the  class  Hexapoda 
(six-legged),  and  for  the  most  part  they  have  six  legs  in  some 
stage  of  their  existence.  Those  attacking  trees  may  be  divided 
roughly  into  two  groups:  (1)  chewing  insects,  and  (2)  sucking 
insects.  The  chewing  insects  (except  termites  or  white  ants) 
have  four  distinct  stages  in  their  life  cycles  as  follows:  (1)  egg, 
(2)  caterpillar,  grub  or  larva,  (3)  pupa,  (4)  adult  insect.  Such 
insects  are  said  to  have  complete  transformations.  The  sucking 
insects  have  incomplete  transformations  and  do  not  pass  through 
these  four  well-marked  stages.  There  is  usually,  though  not 
always,  an  egg  stage,  and  an  adult  stage,  but  there  is  no  distinct 
pupa,  except  in  case  of  the  males  in  certain  scale  insects  and  white 
flies,  and  the  larvae  are  called  nymphs  after  hatching  from  the 
eggs,  and  undergo  a  gradual  development,  molting  several  times 
with  only  slight  changes  until  the  adult  stage  is  reached. 

Chewing  insects  have  strong  jaws  or  mandibles  with  which 
they  bite  or  tear  oil  bits  of  the  food  which  they  swallow.  Suck- 
ing insects  have  beaks  or  probosces  which  they  insert  into  the 
tissues  and  suck  out  the  sap. 


insecticide  formulas  157 

Common  Insecticides 

Remedies  for  chewing  insects  include  the  arsenical  poisons, 
but  these  are  not  effective  against  sucking  insects  where  it  is 
necessary  to  employ  some  substance  which  will  kill  by  contact. 
Both  kinds  of  insects  may  be  killed  by  fumigation. 

The  most  common  arsenical  poison  used  in  tree  spraying  is 
lead  arsenate,  which  may  now  be  obtained  in  the  form  of  paste, 
and  also  as  a  dry  powder.  It  is  used  in  various  proportions  from 
three  pounds  of  paste  or  one  and  one-half  pounds  of  dry  powder 
in  orchards,  to  10  pounds  of  paste  or  five  pounds  of  dry  powder 
to  50  gallons  of  water  for  gipsy  moth  and  certain  other  shade  tree 
insects.    A  spreader  is  sometimes  employed. 

FORMULA  FOR  LEAD  ARSEN.\TE 

Lead  arsenate  (paste) 3-10  lbs.  or   (dry)   l}4-5  lbs. 

Calcium  caseinate  spreader 1  lb. 

Water 50  gals. 

Paris  green  and  calcium  arsenate  are  often  used  in  spraying 
especially  on  potatoes.  Calcium  arsenate  is  used  extensively  on 
cotton  in  the  South,  but  it  causes  injury  on  apple  foliage  in  Con- 
necticut, and  is  not  recommended  for  tree  work.  In  case  it  seems 
necessary  to  use  these  poisons,  }i  lb.  of  Paris  green,  1^  lbs.  air- 
slaked  or  hydrated  lime  may  be  used  to  50  gallons ;  with  calcium 
arsenate,  1^  lbs.  each  of  the  poison  and  lime  may  be  used  to  50 
gallons  of  water. 

FORMULA  FOR   NICOTINE  SOLUTION 

Nicotine  sulphate  may  be  obtained  in  40  per  cent,  solution,  and 
several  dift'erent  brands  are  on  the  market.  Used  to  kill  aphids 
and  other  sucking  insects. 

Nicotine   sulphate 14  pint 

Laundry    soap 2  lbs.  or 

Calcium  caseinate 1    lb. 

Water 50  gals. 

Nicotine  sulphate  solution  may  be  added  to  lead  arsenate  if 
desired,  but  the  soap  should  be  omitted. 

LIME-SULPHUR  WASH 

Liquid  lime-sulphur 1  gal. 

Water 9  gals. 

This  is  used  as  a  dormant  spray  to  kill  scale  insects,  and  is  also 
a  good  fungicide.  Dry  lime-sulphur  preparations  are  now  on  the 
market  and  in  using  them,  directions  on  the  package  should  be 
followed.  Diluted  mixtures  of  lime-sulphur  are  also  used  on  the 
foliage  as  a  fungicide. 


158  CONNECTICUT    EXPERIMENT    STATION  BULLETIN   263. 

MISCIBLE  OILS 

There  are  several  tniscible  oils  on  the  market,  and  these  may  be 
used  at  th6  rate  of  one  part  in  15  parts  of  water  as  a  dormant 
spray  to  kill  scale  insects,  and  1-20  for  spruce  gall  aphid. 

Lraf-Chewing  Insects 

Elm  Leaf  Beetle:  The  elm  leaf  beetle,  Galenicella  xaniJwme- 
laena  Schrank,  hibernates  in  attics,  belfries  and  other  protected 
places,  emerges  from  its  hiding-  place  in  early  spring  and  eats 
holes  in.  the  expanding  leaves  in  May.  The.  sexes  mate  and  the 
females  deposit  on  the  under  sides  of  the  leaves,  clusters  of  flask- 
shaped.  yelloAV  eggs,  which,  in  a  normal  season,  hatch  about 
June  1.  The  larvae  or  grubs  feed  upon  the  green  tissue  on  the 
under  surface,  skeletonizing  the  leaves.  When  numerous  they 
leave  only  the  veins  and  the  upper  epidermis,  and  such  injured 
leaves  turn  brown  and  fall,  usually  the  latter  half  of  July.  At 
this  time  the  larvae  reach  their  maturity,  drop  to  the  "ground  or 
crawl  down  the  trunk,  and  on  the  ground  around  the  base  of  the 
tree  transform  to  bright  3^ellow  pupae.  About  10  days  later  the 
beetles  appear  and  go  to  the  trees,  some  laying  eggs  for  a  second 
generation,  which  seldom  or  never  does  any  harm  in  Connecti- 
cut. The  late  emerging  beetles  probably  do  not  lay  eggs,  but  fly 
about  and  feed  more  or  less  and  go  early  into  their  winter  quar- 
ters. 

This  insect,  like  humans,  congregates  in  cities  and  towns,  and 
seldom  injures  trees  in  the  open  country.  It  is  even  more 
injurious  to  European  elms  than  to  the  American  elm.  It  was 
troublesome  in  ]  923  and  defoliated  trees  in  some  localities. 
There  was  little  rainfall  during  the  pupating  period,  and  most  of 
the  larvae  came  through  to  the  adult  stage.  When  pupation  takes 
place  during  a  wet  period,  the  pupae  are  often  attacked  and 
killed  by  a  white  mold  or  fungus.  Sporotrichmn  globulifencni 
Speg.  {entomophiluin  Peck.)  This  fungus  and  the  moisture 
were  absent  at  the  time  of  pupation  in  both  1923  and  1924: ;  con- 
sequently the  elm  leaf  beetle  bids  fair  to  be  abundant  and  to 
cause  injury  to  the  trees  in  1925.  In  1924,  the  season  was  late 
and  the  insect  went  through  its  different  stages  and  defoliated 
the  trees  much  later  than  normal. 

The  remedies  are  to  kill  the  beetles  in  attics  and  belfries,  and 
to  kill  the  pupae  on  the  ground  around  the  trunks  of  the  trees  by 
spraying  them  with  nicotine  solution  and  soap,  and  to  spray  the 
foliage,  particularly  the  under  surface,  about  June  1,  with  lead 
arsenate,  two  to  three  pounds  of  the  dry  powder  in  50  gallons  of 
water. 

Further  information  regarding  this  insect  may  be  obtained 
from  Bulletin  155  of  this  Station. 


LEAF-CHEWING    INSECTS  159 

Tent  Caterpillar:  The  tent  caterpillar,  Malacosoina  aiiieri- 
cana  Fabr.,  usually  confines  its  attacks  to  wild  cherry  and 
apple,  but  it  is  very  abtmdant  every  10  or  12  years  when  it  may 
also  attack  oak  and  other  trees.  The  eggs  are  deposited  in  July 
in  cylindrical  masses  around  the  small  twigs,  and  covered  with  a 
gray,  glue-like  substance,  probably  for  protection.  These  eggs 
hatch  when  the  leaf  buds  first  open  in  April,  and  the  young  cater- 
pillars from  each  egg-cluster  live  and  feed  together  and  form 
a  web  or  tent  in  the  crotch  of  the  tree  or  in  a  fork  of  one  of  its 
branches.  The  caterpillars  go  outside  of  the  nest  twice  a  day  to 
feed,  and  enter  it  after  feeding,  except  when  nearly  full-grown 
they  cluster  on  the  outside  of  the  nest.  The  caterpillars  become 
full-grown  about  the  first  week  in  June  and  make  their  light 
yellow  cocoons  under  rubbish,  fence  rails,  etc.,  near  the  ground. 
The  reddish-brown  moths  emerge  two  weeks  later.  There  is 
only  one  brood  each  year. 

The  remedies  are  cutting  off  and  burning  the  egg-clusters  in 
winter,  removing  the  nests  and  caterpillars  with  a  caterpillar 
brush,  or  burning  them  ofif  with  a  torch,  and  spraying  the  foliage 
with  lead  arsenate. 

Additional  information  on  the  tent  caterpillar  may  be  found 
in  Bulletin  177  of  this  Station. 

Cankerworms :  The  fall  cankerworm,  Alsophila  pometaria 
Harris,  is  a  common  pest  of  fruit,  shade  and  woodland  trees  in 
Connecticut,  and  in  some  cases  is  accompanied  by  the  spring 
cankerworm,  Paleacrita  vernata  Peck,  which  is  usually  much  less 
abundant.  Both  species  cause  the  same  kind  of  injury,  and 
require  similar  remedies.  Both  have  winged  males  and  wingless 
females  which  crawl  up  the  trees  to  lay  eggs.  The  moths  of  the 
fall  cankerworms  emerge  during'  the  warm  days  of  November 
and  December  and  the  females  lay  eggs.  The  adults  of  the  spring 
cankerworm  emerge  and  lay  their  eggs  in  ^Nlarch.  The  eggs  of 
both  species  hatch  with  the  first  opening-  buds  and  the  larvae  feed 
upon  the  leaves  of  fruit,  shade  and  woodland  trees.  Canker- 
worms  were  so  abundant  in  Greenwich  and  Stamford  in  1924 
that  small  woodland  areas  and  many  shade  trees  were  entireh' 
defoliated.  The  caterpillars  normally  feed  during  May,  becoming 
full-grown  about  June  1st,  and  during  the  first  week  in  June  go 
into  the  ground  and  transform  to  naked  brown  pupae,  remaining 
in  this  stage  until  the  following  November  and  December,  or  in 
case  of  the  spring  species,  until  the  following  ~\Iarch.  In  the  fall 
of  1923  the  male  moths  were  very  abundant  flying  about  and 
clustering  on  tree  trunks,  especially  on  the  warm,  foggy  days  of 
November  and  December. 

Ihere  are  two  preventive  methods :  Spraying  the  foliage  with 
lead  arsenate  during  May,  and  employing  stickv  bands  to  pre- 
vent the  insects  ascending  the  trees.     The  spraying  should  be 


160  CONNECTICUT    EXPERIMENT    STATION  BULLETIN   263. 

done  just  as  early  as  is  possible  after  the  leaves  have  unfolded 
enough  to  catch  and  hold  the  poison.  By  using  a  strip  of  cotton 
batting  to  fill  the  crevices  in  the  bark  covering  this  with  a  5-inch 
strip  of  single  pl}^  tarred  paper  tacked  at  the  lap,  tree  tanglefoot 
can  be  applied  to  the  paper  band.  It  should  be  kept  sticky  during 
November  and  December,  and  again  during  March  and  April 
when  the  eggs  hatch.  The  whole  may  be  removed  without  dis- 
figuring the  trees. 

Further  information  may  be  obtained  from  Bulletin  No.  1238, 
United  States  Department  of  Agriculture. 

Tussock  Moths:  The  white-marked  tussock  moth,  Hemero- 
campa  leucostigma  S.  and  A.,  often  injures  and  defoliates  elm, 
maple,  linden,  poplar,  horse  chestnut  and  other  trees  in  cities  and 
towns.  The  caterpillars  are  bright  colored  and  conspicuous, 
being  striped  lengthwise  with  yellow  and  brown,  and  having  a  red 
head  and  three  long  black  tufts  or  pencils  of  hairs,  two  near  the 
head  and  one  at  the  tail.  There  are  four  white  tufts  on  the  front 
half  of  the  body.  There  are  two  generations  each  year  in  Con- 
necticut, one  at  Albany,  N.  Y.,  and  three  in  Washington,  D.  C. 
The  insect  winters  in  the  form  of  egg-clusters,  usually  on  or  near 
the  old  cocoons  on  the  trees  and  covered  with  a  frothy  white 
substance  about  half  an  inch  in  diameter.  The  eggs  hatch  in  May 
and  the  caterpillars  become  full-grown  about  the  first  of  July, 
and  make  their  cocoons  on  the  bark  of  the  trees.  Two  week 
later  the  moths  emerge.  The  eggs  for  the  second  brood  are  laid 
in  July  and  the  caterpillars  feed  through  August  and  September, 
then  pupate,  and  the  females  lay  eggs  that  carry  over  the  winter. 

The  females,  like  the  cankerworms,  are  without  wings,  but  as 
they  pupate  on  the  trees,  banding  is  not  so  helpful.  The  males 
are  mouse  color  with  characteristic,  rather  indistinct  markings, 
and  are  attracted  by  lights. 

Spraying  the  foliage  and  gathering  and  destroying  the  egg- 
clusters  are  the  common  methods  of  control. 

For  further  information,  see  Report  of  this  Station  for  1916, 
page  105. 

The  hickory  tussock  moth,  Halisidota  caryae  Harris,  and  the 
tessellated  tussock  moth,  //.  tessellaris  S.  and  A.  both  have  tufted 
caterpillars  which  feed  upon  apple,  oak,  hickor)^,  willow,  poplar 
and  other  trees,  and  occasionally  may  require  a  spray  of  lead 
arsenate  to  prevent  damage.     Each  species  is  single-brooded. 

For  further  information,  see  Report  of  this  Station  for  1917, 
page  325. 

Gipsy  Moth  and  Brovi^n-tail  Moth:  The  caterpillars  of  the 
gipsy  moth,  Forthetria  dispar  Linn.,  when  abundant  feed  upon  the 
foliage  of  apple,  oak,  birch,  maple,  willow,  poplar,  and  even 
conifers.  There  is  one  generation  each  season ;  the  eggs  are  laid 
in  clusters  on  the  bark  or  in  cavities  in  trees,  during  July  and 


LEAF-CHEWING    INSECTS  161 

August,  and  hatch  the  following  May.  Caterpillars  become 
mature  the  last  of  June  and  make  their  cocoons  in  protected 
places.  The  adults  emerge  two  weeks  later.  Soaking  the  egg- 
clusters  with  creosote,  and  spraying  the  foliage  with  lead  arsenate 
with  four  to  five  poimds  of  dry  lead  arsenate  in  50  gallons  of 
water,  are  the  most  approved  methods  of  artificial  control.  So 
far,  this  insect  has  been  kept  in  check  in  Connecticut  by  the  forces 
employed  by  the  state. 

Further  information  regarding  this  insect  mav  be  found  in 
Bulletin  186  of  this  Station. 

The  brown-tail  moth,  Euproctis  chrysorrhoea  Linn.,  formerly 
occurred  over  the  eastern  half  of  Connecticut,  but  has  since 
disappeared  and  for  several  years  has  not  been  seen.  It  was 
evidently  controlled  bv  natural  enemies,  and  it  may  come  back 
again.  The  caterpillars  feed  upon  pear,  apple,  plum,  cherr\',  oak, 
elm  and  maple,  and  live  through  the  winter  in  a  partially  grown 
state  in  small  webs  on  terminal  branches.  Brown  egg-masses 
are  laid  on  the  under  side  of  leaves  in  July  by  the  white  moths 
with  brown  tufts  at  the  end  of  their  bodies.  The  caterpillars 
when  touched  by  human  hands  cause  a  rash ;  they  become  mature 
in  June  and  make  their  cocoons  on  the  leaves. 

The  remedies  are  to  clip  off  and  burn  the  winter  nests,  and  to 
spray  the  foliage  in  May  with  lead  arsenate. 

More  detailed  information  may  be  found  in  Bulletin  182  of 
this  Station. 

Fall  Webworm:  The  fall  webworm,  Hyphaiitria  cunea 
Drury,  is  found  on  all  kinds  of  fruit,  shade  and  woodland  trees 
the  last  half  of  summer,  the  caterpillars  feeding  upon  leaves 
enclosed  in  nests  near  the  ends  of  the  branches.  There  is  a  par- 
tial second  brood  in  Connecticut,  and  the  eggs  are  laid  on  the 
under  side  of  leaves  by  the  white  female. 

Clipping  off  and  burning  these  nests,  and  spraying  the  trees 
with  lead  arsenate  are  the  remedies. 

For  further  information,  see  Report  of  this  Station  for  1917, 
page  319. 

Walnut  Caterpillar:  Hickory,  butternut  and  black  walnut 
trees  are  often  stripped  of  their  leaves  in  late  summer  by  the  wal- 
nut caterpillar,  Datana  intcgerriiua  G.  &  R.  This  is  a  black 
caterpillar  covered  with  whitish  hairs,  which  feeds  gregariously. 
The}'  molt  and  leave  the  cast  skins,  in  the  form  of  gray  patches 
on  the  tree  trunks.     Spraying  with  lead  arsenate  is  the  remedy. 

For  further  information,  see  Report  of  this  Station  for  1917, 
page  326. 

Sawflies  on  Conifers :  There  are  several  species  of  sawflies,  the 
larvae  of  which  feed  on  the  various  species  of  pine  trees,  occa- 
sionally defoliating  them.  One  of  the  most  destructive  is  the 
imported  pine  sawrly,  Diprion  simile  Hartig,  which  attacks  the 


162  CONNECTICUT   EXPERIMENT    STATION  BULLETIN   263. 

white  pine  and  other  five-needled  pines ;  these  may  also  be 
attacked  by  Neodiprion  pmetum  Norton,  Neodiprion  lecontei 
Norton,  and  other  species  feed  upon  the  pitch  pine  and  other 
kinds  of  pines. 

The  larch  sawfly,  Lygaeonematus  erichsoni  Hartig,  is  occa- 
sionally so  abundant  as  to  defoliate  larch  trees,  and  sometimes 
spruce  trees  are  injured  by  Neodiprion  abietis  Harris.  The 
proper  remedy  against  all  these  pests  is  spraying  with  lead  arse- 
nate. 

For  further  information  regarding  the  imported  pine  sawfly, 
see  Report  of  this  Station  for  1917^  page  273. 

Larch  Leaf -miner  or  Case  Bearer:  This  insect,  Coleophora 
laricdla  Hubn.,  is  a  small  moth  and  the  larva  tunnels  inside  the 
leaves  from  June  to  September,  often  ruining  them.  It  then 
migrates  to  the  twigs,  where  in  brown,  cigar-shaped  cases  it  passes 
the  winter.  A  dormant  spray  with  liquid  lime-sulphur  in  early 
spring  will  kill  the  larvae  in  their  winter  cases  and  is  the  best 
remedy  known. 

Further  information  may  be  foimd  in  the  above  mentioned 
Report,  page  288. 

Arbor-vitae  Leaf -Miner:  This  small  moth,  Argyresthia 
thnieUa  Packard,  has  recently  caused  serious  injur}^  to  arbor-vitae 
trees  and  hedges  in  Connecticut.  The  tiny  larvae  tunnel  inside 
the  leaves,  causing  them  to  appear  transparent  and  later  turn  yel- 
low and  brown.  The  adults  emerge  late  in  May  and  early  in 
June,  and  spraying  with  nicotine  solution  and  soap  when  the 
adults  are  flying  and  laying  eggs  will  materially  reduce  the  pest. 

For  further  information,  see  Report  of  this  Station  for  1921, 
page  157. 

Imported  Willow  Leaf  Beetle:  This  small,  shiny  blue  beetle, 
Plagiodera  versicolora  Laich.,  has  been  brought  into  this  country 
and  has  spread  from  the  vicinity  of  New  York  to  various  parts 
of  Connecticut.  It  prefers  shiny  leaved  willows,  but  may  attack 
poplars.  Eggs  are  laid  on  the  leaves  and  both  beetles  and  grubs 
feed  upon  the  leaves,  skeletonizing  them.  There  are  two  com- 
plete broods  each  season,  and  the  beetles  hibernate.  The  remedy 
consists  of  spraying  with  lead  arsenate. 

For  further  information,  see  Report  of  this  Station  for  1921, 
page  195. 

Bii-ch  Leaf  Skeletonizer :  The  larvae  of  a  small  moth,  Bnccu- 
latrix  canadensisella  Chambers,  often  skeletonize  the  leaves  of 
gray,  white  and  yellow  birch  trees  late  in  the  season.  There  is 
only  one  annual  generation,  and  the  insect  passes  the  winter 
in  cocoons  on  the  fallen  leaves.  The  remedy  consists  of  spraying 
with  lead  arsenate  during  August. 

For  further  information,  see  Report  of  this  Station  for  1910, 
page  701. 


BORERS    OR   WOOD-CHEWING   INSECTS  163 

Spiny  Elm  Caterpillar:  Black,  spiny  caterpillars  are  often 
found  feeding  gregariously  on  elm,  poplar  and  willow,  stripping 
the  branches.  This  insect  is  called  the  spiny  elm  caterpillar,  and 
is  the  larva  of  the  mourning  cloak  or  Antiopa  butterfly,  Euvanessa 
antiopa  Linn.  There  are  two  broods  each  year  in  Connecticut, 
and  the  adult  butterflies  live  through  the  winter  and  may  be  seen 
flying  on  warm  days.  As  the  caterpillars  feed  in  colonies  it  is 
often  possible  to  crush  them  on  the  tree  or  after  cutting  off  the 
infested  branches.  Spraying  the  foliage  with  lead  arsenate  is  a 
remedy. 

For  further  information,  see  Report  of  this  Station  for  1906, 
page  260. 

Borers  or  Wood-Chewing  Insects 

Maple  Borer:     Sugar  maple  trees  are  commonly  injured  by  the 

maple  borer,  Glycohiiis  speciosus  Say,  a  handsome  black  beetle 
with  yellow  markings,  and  about  an  inch  in  length.  A  conspicu- 
ous mark  is  the  W  on  the  base  of  the  wing-covers.  The  beetles 
appear  in  Connecticut  the  first  half  of  July,  and  a  little  later  the 
eggs  are  laid.  The  tiny  grub  begins  tunneling  in  the  bark,  soon 
entering  the  sapwood,  where  it  works  around  the  trunk  or  branch, 
usually  going  upward  in  a  spiral  course.  Two  years  are  probably 
required  for  the  complete  life  cycle,  and.  of  course,  the  grub 
increases  in  size  with  age  and  makes  a  much  larger  burrow  when 
it  is  nearly  full-grown.  This  results  in  some  large  scars  on  the 
trees,  and  when  two  or  more  grubs  are  at  work  in  the  same  trunk, 
they  sometimes  girdle  it  and  the  tree  breaks  over.  When  mature, 
the  grub  pupates  in  the  burrow  and  emerges  the  following  July 
through  a  nearly  circular,  somewhat  flattened  hole,  nearly  half 
an  inch  in  diameter.  The  best  control  measure  is  to  examine 
trunk  and  branches  of  choice  maple  trees,  preferably  in  Septem- 
ber, find  the  grubs  by  following  up  the  sawdust  emitted,  and  cut 
them  out  or  kill  by  inserting  a  wire  in  the  burrow.  Also  destroy 
the  adult  beetles  when  found  resting  on  the  trunks  of  trees  in 
July. 

For  further  information,  see  Report  of  this  Station  for  1922, 
page  851. 

Leopard  Moth:  Elm,  maple  and  other  shade  trees  as  well  as 
fruit  trees  are  attacked  by  the  leopard  moth,  Zeuzera  pyrina  Linn. 
The  female  moth  has  a  wing-spread  of  about  two  and  a  half 
inches,  is  white  with  fore-wings  coarsely  dotted  with  blue  and 
black  spots.  The  male  is  smaller  though  similarly  marked.  The 
moths  emerge  mostly  in  July.  Eggs  are  laid  in  crevices  in  the 
bark,  and  the  young  caterpillars  usually  enter  the  twigs  at  the 
base  of  a  bud,  and  after  feeding  for  a  time,  leave  their  burrows 
and  enter  larger  branches  where  they  excavate  large,  irregular 
galleries.    The  branches  are  weakened  and  often  break  ofif.    The 


164  CONNECTICUT    EXPERIMENT   STATION  BULLETIN   263. 

grub  is  white  or  pinkish,  with  head,  neck  shield  and  tubercular 
spots,  black;  it  is  nearly  three  inches  long  when  fully  grown. 
The  borer  causes  most  of  its  damage  the  second  summer,  lives 
in  the  burrow  the  following  winter  and  pupates,  the  moths  emerg- 
ing in  July,  two  years  being  necessary  for  its  complete  life  cycle. 
A  systematic  cutting  and  burning  of  infested  branches  will  check 
the  pest,  and  where  sawdust  is  thrown  out  from  the  main  trunk 
and  larger  branches  it  is  possible  to  dig  out  the  borers.  A  wire 
may  be  inserted  in  the  burrow  or  a  few  drops  of  carbon  disulphide 
injected  and  the  opening  closed  to  kill  the  borers. 

For  further  information,  see  Report  of  this  Station  for  1911, 
page  317. 

Bronze  Birch  Borer:  Many  European  white  birches,  par- 
ticularly the  cut-leaf  form,  have  been  killed  during  the  past  few 
years  by  the  bronze  birch  borer,  Agrilus  anxius  Gory.  This  small 
beetle  begins  its  attack  on  the  branches  in  the  upper  part  of  the 
tree  and  spiral  swellings  or  ridges  show  on  the  surface  of  the 
bark.  Later  the  lower  branches  are  similarly  affected  and  the  tree 
is  soon  killed.  Native  species,  though  not  immune,  are  less  sus- 
ceptible to  injury.  If  a  tree  becomes  generally  infested,  it  can- 
not be  saved.  The  beetles  emerge  in  June,  feed  for  a  time  on  the 
leaves  and  lay  eggs  in  slits  in  the  bark.  There  is  only  one  brood 
annually  and  the  grubs  make  shallow  galleries  in  the  sap  wood 
just  beneath  the  bark.  Where  a  few  branches  are  infested,  they 
should  be  cut  off  and  burned  in  early  spring.  Dead  trees  should 
also  be  burned  before  the  beetles  emerge.  As  the  beetles  feed 
somewhat  on  the  leaves,  the  trees  should  be  well  coated  with  lead 
arsenate  early  in  June. 

For  further  information,  see  Report  of  this  Station  for  1922, 
page  359. 

The  Twigf  Pruner:  Small  terminal  twigs  of  oak  and  some 
other  trees  are  often  cut  oft'  by  a  borer  in  late  summer  and  fall 
upon  the  ground.  This  is  the  work  of  the  twig  pruner,  Hyper- 
mallits  villosufu  Fabr.,  one  of  the  long-horned  beetles.  There 
is  only  one  brood_  each  year  and  the  borer  usually  drops  to  the 
ground  in  the  base  of  the  severed  twig.  Consequently,  gathering 
and  burning  these  twigs  is  advisable,  and  about  the  only  control 
measure  known.  Trees  are  not  seriously  injured  by  the  attacks 
of  this  insect. 

For  further  information,  see  Bulletin  382,  Ohio  Agr.  Expt.  Sta- 
tion,, page  327, 

Carpenter  Worm:  Large  grubs,  occasionally  found  tunneling 
in  the  heart  wood  of  ash,  elm,  and  other  trees,  are  called  carpen- 
ter worms,  and  are  the  larvae  of  one  of  the  Cossid  or  goat  moths, 
Prionoxystus  rohUiiae  Peck.  It  is  related  to  the  leopard  moth, 
and  there  is  one  generation  each  year.     About  the  only  remedy 


BORERS    OR   WOOD-CHEWING    INSECTS  165 

is  to  inject  carbon  disulphide  into  the  burrows  and  close  the  open- 
ing, or  cut  out  the  grubs. 

For  further  information,  see  Bulletin  332,  Ohio  Agr.  Expt. 
Station,  page  329. 

Locust  Borer  and  Painted  Hickory  Borer:  Young  locust 
trees  are  often  killed  or  deformed  by  the  locust  borer,  Cyllene 
rohiniae  Forst.,  and  hickory  trees  are  less  seriously  injured  by  a 
closely  related  species  called  the  painted  hickory  borer,  Cyllene 
pictus  Drury.  In  fact,  some  claim  that  these  two  species  are 
identical,  but  there  are  slight  structural  differences  and  the  adult 
of  the  painted  hickory  borer  emerges  in  the  spring,  while  the 
locust  species  appears  in  the  fall.  Both  are  long-horned,  black 
beetles,  three-fourths  of  an  inch  in  length,  marked  with  narrow 
cross-bands  of  greenish  yellow  and  with  a  W-shaped  mark  on 
the  base  of  the  wing  covers.  The  life  cycle  of  each  occupies 
about  a  year.  Dr.  Craighead  reports  success  by  injecting  into 
the  burrows  kerosene  soap  emulsion  made  with  water  containing 
five  per  cent,  of  sodium  arsenate. 

For  further  information,  locust  borer,  see  Bulletin  787,  U.  S. 
Department  of  Agriculture:  Painted  hickory  borer.  New 'York 
State  Aluseum  Memoir  8.  page  264. 

Saperda  Borers:  Linden  trees  are  often  injured  by  the  linden 
borer,  Saperda  vesiita  Say,  hickory  by  the  hickory  borer,  Saperda 
disc  aid  ea  Fabr.,  poplars  by  the  poplar  borer,  Saperda  calcarata 
Say,  elms  by  the  elm  borer,  Saperda  tridentata  Oliv.,  and  apple 
by  the  round-headed  apple  borer,  Saperda  Candida  Fabr.  Trees 
badly  infested  with  the  elm  borer  should  be  cut  and  burned. 
These  borers  are  usually  cut  out,  but  carbon  disulphide  may  be 
employed  and  possibly  the  poisoned  kerosene  emulsion  may  prove 
successful. 

For  further  information  regarding  these  borers,  see  Manual  of 
Tree  and  Shrub  Insects. 

White  Pine  Weevil:  The  leaders  or  top-most  shoots  of  young 
white  pine  trees  are  commonly  attacked  and  killed  by  a  snout 
beetle,  Pissodes  strohi  Peck,  which  lays  eggs  in  punctures  in  the 
bark  of  the  leader  during  May.  Numerous  grubs  hatching  from 
these  eggs  tunnel  in  the  stem,  becoming  full-grown  about  July  1, 
and  pupate  in  oval  cells  in  the  wood.  The  leaders  wilt  and  die 
during  July.  Repeated  attacks  cause  the  trees  to  become  crooked, 
forked  and  ill-shaped.  It  is  commonly  recommended  that  the 
leaders  be  cut  off  and  burned  before  the  adults  emerge,  or  still 
better,  place  them  in  cages  which  will  permit  the  escape  of  their 
parasites  but  not  of  the  snout-beetles.  Small  plantations  and 
choice  ornamental  trees  may  be  protected  to  some  extent  by  spray- 
ing the  leaders  about  May  1,  with  liquid  lime-sulphur  (1-9)  or 
lead  arsenate,  or  by  jarring  the  leaders  twice  a  week  for  six  weeks 
and  catching  the  beetles  in  a  net. 


166  CONNECTICUT    EXPERIMENT    STATION  BULLETIN   263. 

For  further  information,  see  Report  of  this  Station  for  1919, 
page  141. 

The  Hickory  Bark  Beetle  and  Other  Bark  Beetles:  Hickory 
trees  are  beset  more  or  less  periodically  by  epidemic  attacks  of  the 
hickory  bark  beetle,  Scolytus  quadrispinosus  Say,  which  breeds 
in  the  cambium,  effectually  girdling  the  tree.  Later  the  exit  holes 
give  the  tree-the  appearance  of  having  been  punctured  with  shot. 
Thousands  of  hickory  trees  have  been  killed  in  Connecticut  by 
this  insect  during  the  past  25  years.  The  adults  feed  on  the  leaf 
petioles,  and  a  thorough  spraying  of  the  foliage  about  July  1, 
with  lead  arsenate  and  nicotine  sulphate  is  believed  to  be  of  some 
benefit.  Badly  infested  trees  should  be  cut  and  burned  or  barked 
before  the  beetles  emerge.  Related  bark  beetles  with  similar 
habits  attack  pine,  spruce  and  other  kinds,  usually  the  unthrifty 
trees.  Keep  all  trees  as  vigorous  as  possible.  Cutting  and  burn- 
ing the  infested  trees  will  generally  check  the  outbreak. 

For  further  information,  see  Manual  of  Tree  and  Shrub 
Insects. 

The  Parandra  Borer  and  the  Maple  Sesian:  Weakened  trees 
of  nearly  all  kinds  are  attacked  by  a  brown  beetle  known  as  the 
Paranda  borer,  Parandra  brunnea  Fabr.,  which  tunnels  in  the 
heartwood  near  the  ground.  The  maple  sesian  is  a  clear-wing 
moth,  Sesia  acerni  Clem.,  which  breeds  in  the  vicinity  of  wounds 
on  the  trunk  and  branches,  particularly  of  soft  maples.  Care- 
ful dressing  of  the  wounds  is  a  good  preventive.  Where  trees 
are  kept  in  a  thrifty  condition  there  is  little  injury  from  either  of 
these  insects. 

For  further  information,  see  Report  of  this  Station  for  1921, 
page  201  (Parandra  borer),  and  for  1922,  page  355  (maple 
sesian). 

Pigeon  Tremex:  The  pigeon  tremex,  or  horn-tail,  Tremex 
columha  Linn.,  is  a  borer  in  dead  and  dying  trees  of  nearly  all 
deciduous  kinds,  and  is  common  in  maple,  elm  and  hickory. 
Round  holes  the  size  of  a  lead  pencil  mark  the  points  of  exit  of 
the  adults,  which  are  rather  large,  four-winged  flies,  about  two 
inches  in  length,  marked  with  yellow  and  black  and  with  a  con- 
spicuous horn  or  ovipositor  at  the  rear  end  of  the  body.  Trees 
which  are  infested  by  the  pigeon  horn-tail  are  commonly  visited 
by  two  of  its  very  conspicuous  parasites  called  "long  stings." 
In  fact,  the  parasites  are  usually  the  first  indication  to  the  owner 
that  anything  is  wrong  with  his  tree,  and  he  thinks  them  respon- 
sible for  the  injury.  The  black  long-sting,  Megarhyssa  atrata 
Fabr.,  and  the  lunate  long-sting,  Megarhyssa  lunator  Fabr.,  are 
among  the  largest  of  the  parasitic  Ichneumon  flies,  and  the 
females  have  bristle-like  ovipositors  nearly  four  inches  in  length 
and  resembling  horse  hairs. 

For  further  information,  see  Manual  of  Tree  and  Shrub 
Insects. 


SUCKING   INSECTS  167 

Carpenter  Ant  and  Termites*  Trees  are  often  tunneled  and 
honeycombed  by  the  large,  black,  carpenter  ant,  Camponotus 
herculeamis  pennsylvanictis  DeGeer,  and  by  the  so-called  white 
ants  or  termites,  Reculitermes  flavipes  Kollar.  The  white  ants 
are  white  only  in  their  immature  stages,  the  adults  being  brown. 
The  best  remedy  for  both  species  is  to  inject  carbon  disulphide 
and  confine  it  in  the  burrows  by  plugging  the  opening. 

For  further  information,  see  Report  of  this  Station  for  1922, 
page  365. 

Sucking  Insects 

Spruce  G-all  Aphid :  Cone-shaped  galls  at  base  of  new  growth 
on  Norway,  black,  white  and  red  spruce  trees  are  caused  by  the 
spruce  gall  aphid,  Chernies  abietis  Linn.  This  insect  has  two  gen- 
erations each  year  the  winter  being  passed  by  the  immature 
females  on  the  twigs,  and  particularly  around  the  buds  and  under 
the  bud  scales.  They  reach  maturity  in  spring,  and  lay  their  eggs 
about  May  1.  The  young  cluster  at  the  tips  where  the  new 
growth  starts,  and  form  the  cone-shaped  galls.  The  insects 
become  mature  in  August  and  escape  from  the  galls  and  lay  eggs 
for  the  second  brood.  Another  species  Chermes  cooleyi  Gillette, 
makes  larger  galls  on  the  Colorado  blue  spruce.  Thoroughly 
spraying  with  nicotine  solution  and  soap,  or  with  a  miscible  oil 
(1-20)  in  the  fall  or  spring  will  hold  this  pest  in  check.  Clippmg 
off  and  burning  the  galls  in  early  summer  can  also  be  practiced 
on  small  trees. 

For  further  information  see  Report  of  this  Station  for  1922, 
page  357. 

Leaf  Aphids:  There  are  many  kinds  of  aphids  which  injure 
the  various  kinds  of  trees  by  sucking  sap  from  the  leaves.  Some 
of  these  are:  Green  apple  aphid.  Aphis  pomi  DeG.,  rosy  apple 
aphid,  Anuraphis  rnseus  Baker,  of  apple;  woolly  aphid  of  apple 
and  elm,  Eriosoma  lanigera  Hausm. ;  woolly  beech  aphid,  Proci- 
philiis  imhricator  Fitch ;  birch  aphid  Calaphis  betulaecolens 
Fitch ;  pine  bark  aphid.  Chermes  pinicorticis  Fitch,  and  many 
other  species.  As  a  rule,  these  aphids  may  be  held  in  check  by 
spraying  with  nicotine  solution  and  soap.  Calcium  caseinate  may 
be  used  as  a  spreader  in  place  of  soap.  Dusts  containing  nico- 
tine may  also  be  blown  upon  the  leaves. 

Further  information  may  be  obtained  from  Manual  of  Tree  and 
Shrub  Insects. 

Hickory  G-all  Aphid:  The  compound  leaves  of  hickory  are 
often  distorted  and  fall  in  midsummer  on  account  of  the  attacks 
of  the  hickory  gall  aphid.  Phylloxera  caryaecaiilis  Fitch,  which 
forms  hollow,  globular  galls  on  the  leaf  petioles,  often  causing 
them  to  break  ofiF.  Apparently  no  control  measures  have  been 
worked  out  for  this  insect. 


168  CONNECTICUT    EXPERIMENT    STATION  BULLETIN   263. 

For  further  information,  see  Manual  of  Tree  and  Shrub 
Insects. 

Oyster-Shell  Scale:  The  oyster-shell  scale,  Lepidosaphes  ulmi 
Linn.,  kills  branches  and  sometimes  entire  trees,  and  attacks  many 
kinds  of  deciduous  trees  and  shrubs.  Some  of-  those  most  com- 
monly attacked  are  ash,  maple,  apple,  poplar,  willow,  butternut, 
birch  and  lilac.  Silver  maple  street  trees  are  sometimes  seriously 
mfested  and  it  makes  the  branches  very  brittle  so  that  they  break 
off  in  storms.  This  insect  has  one  generation  each  year  and 
passes  the  winter  as  white  oval  eggs  under  the  old  female  shells. 
These  eggs  hatch  during  the  last  days  of  May,  and  the  young 
crawl  about  for  several  hours  and  establish  themselves  on  the 
bark,  begin  to  suck  the  sap  and  remain  stationary  afterward.  Late 
in  August,  the  females  become  grown  and  die  after  depositing 
eggs  under  the  shells.  The  shells  are  mussel-shaped,  about  an 
eighth  of  an  inch  long,  and  gray  or  brown,  usually  nearly  the 
color  of  the  bark.  Spraying  with  lime-sulphur  (1-9)  or  miscible 
oil  (1-15)  in  early  spring  has  proved  effective.  Also  a  spray  of 
nicotine  solution  and  soap  or  with  kerosene  emulsion  about  June 
10th  will  kill  the  newly-hatched  young. 

For  further  information  see  Report  of  this  Station  for  1903, 
page  229. 

San  Jose  Scale:  This  is  a  small,  circular  scale,  grayish  in 
color  and  about  one-sixteenth  of  an  inch  in  diameter.  The  shell 
is  formed  of  concentric  rings  with  a  nipple  in  the  center.  It  is 
called  the  pernicious  or  San  Jose  scale,  Aspidiotus  perniciosus 
Comst.,  and  it  attacks  many  different  kinds  of  trees  and  shrubs, 
but  shows  a  preference  for  fruit  trees  and  shrubs  of  the  rose 
family.  There  are  three  broods  each  year,  and  the  winter  is 
passed  in  a  partially  grown  condition.  The  young  of  the  first 
brood  appear  the  last  days  of  June.  Though  in  part  controlled 
by  natural  enemies,  this  insect  formerly  destroyed  hundreds  of 
fruit  orchards,  and  after  subsiding  as  a  pest  for  several  years, 
is  now  troublesome  again.  A  dormant  spray  of  lime-sulphur 
(1-9)  or  of  miscible  oil  (1-15)  are  the  remedies. 

For  further  information,  see  Bulletin  165  of  this  Station. 

Maple  Woolly  Leaf  Scale:  Sugar  maple  trees  throughout  the 
cities  and  towns  of  Connecticut  are  attacked  and  injured  by  the 
woolly  maple  leaf  scale,  Phenacoccus  acericola  King.  The 
females  are  found  on  the  under  sides  of  the  leaves  in  midsummer 
where  they  produce  their  eggs  in  large  flocculent  masses  of  white 
wax,  resembling  tufts  of  cotton  or  wool.  Badly  infested  leaves 
drop  in  July.  The  male  cocoons  as  well  as  the  winter  cases  of 
the  immature  females  are  placed  in  the  crevices  of  the  bark  of 
the  trunk  and  at  the  base  of  the  larger  branches.  There  are 
three  broods  each  season.  Spraying  the  winter  cocoons  on  the 
dormant  trees  in  March  using  lime-sulphur  (1-9)  with  the  addi- 
tion of  nicotine  has  proved  an  effective  remedy  in  New  Haven. 


SUCKING   INSECTS  169 

For  further  information  see  Report  of  this  Station  for  1905, 
page  226. 

Cottony  Maple  Scale:  Soft  maples  in  the  vicinity  of  Stam- 
ford for  several  years  have  been  badly  infested  with  the  cottony 
maple  scale,  Pulvinaria  vitis  Linn.,  which  also  attacks  many  other 
kinds  of  trees.  This  insect  has  one  generation  each  year  and 
passes  the  winter  in  the  form  of  thin,  brown,  oval,  soft  scales  on 
the  bark  of  the  twigs.  In  early  summer  the  development  of  the 
egg-sac  causes  one  end  of  the  brown  scale  to  be  lifted  by  a  cot- 
ton-like mass  of  white  wax.  The  young  are  crawling  in  July. 
Spraying  the  trees  with  miscible  oil  (1-15)  in  spring  before  the 
buds  start  has  given  good  control. 

For  further  information,  see  Report  of  this  Station  for  1921, 
page  179. 

Terrapin  Scale:  Another  pest  of  soft  maples  is  the  terrapin 
scale,  Lecaniiim  nigrofasciattim  Pergande,  a  small,  reddish,  con- 
vex species  occurring  on  the  smooth  bark  of  the  smaller  twigs. 
Occasionally  the  sugar  and  Norway  maples  and  other  kinds  of 
trees  are  attacked  by  this  scale.  Badly  injured  branches  should 
be  cut  off  and  burned,  and  the  trees  sprayed  in  early  spring  with 
miscible  oil  (1-15)  or  with  a  kerosene  emulsion  containing  20-25 
per  cent,  of  kerosene. 

For  further  information,  see  Report  of  this  Station  for  1921, 
page  183. 

Tulip  Tree  Scale :  The  lower  branches  of  tulip  trees  are  often 
infested  and  killed  by  the  tulip  tree  scale,  Toumeyella  liriodendri 
Gmel.,  which  appears  as  brown  hemispherical  shells  nearly  one- 
third  of  an  inch  in  diameter.  There  is  only  one  brood  each  year, 
and  the  young  hatch  in  September,  establish  themselves  on  the 
bark,  and  pass  the  winter  in  a  partially  grown  state.  The  next 
season  they  continue  to  suck  sap  from  the  branches,  becoming 
mature  in  August,  and  the  honey  dew  drips  upon  the  ground  and 
lower  leaves,  appearing  like  a  coat  of  varnish.  The  best  times  for 
treatment  are  after  the  leaves  drop  in  the  fall,  or  just  before  they 
put  out  in  the  spring.  Liquid  lime-sulphur  (1-9)  or  a  miscible 
oil  which  does  not  contain  phenol,  may  be  used  for  this  purpose. 

For  further  information,  see  Report  of  this  Station  for  1921, 
page  176. 

Elm  Scale:  The  trunks  of  small  elms  and  the  lower  branches 
of  larger  trees  are  often  infested  and  injured  by  a  soft  scale 
called  the  elm  scale,  Gossyparia  spuria  Mod.  This  scale  occurs  in 
longitudinal  rows  in  the  crevices  of  the  bark,  and  is  oval  in  shape, 
chocolate  brown  in  color  margined  by  a  whitish  fringe  of  wax 
filaments.  There  is  only  one  brood  each  year,  winter  being  passed 
in  a  partly  grown  state,  and  the  young  appear  late  in  June. 
Spraying  with  miscible  oil  in  early  spring  is  a  satisfactory  remedy. 

For  further  information,  see  Manual  of  Tree  and  Shrub 
Insects,  page  161. 


170  CONNECTICUT   EXPERIMENT    STATION  BULLETIN    263. 

Pine  Leaf  Scale:  Small  pine  trees  in  protected  places  are 
often  infested  with  the  pine  leaf  scale,  Chionaspis  pinifoliae  Fitch, 
which  appears  as  white  elongated  shells  on  the  needles.  It  attacks 
the  various  species  of  pines  but  seldom  causes  injury  in  exposed 
situations.  There  are  two  generations  each  year,  though  not  well 
defined,  the  young  of  the  first  brood  beginning  to  appear  in  May 
and  the  second  in  July.  It  passes  the  winter  in  the  form  of  purple 
eggs  under  the  shells.  Badly  injured  branches  should  be  cut 
off  and  burned.  Dr  Felt  advises  spraying  with  miscible  oil 
(1-16)  in  spring,  but  it  is  probable  that  summer  applications  of 
nicotine  solution  and  soap  will  also  keep  the  pest  in  check. 

For  further  information,  see  Report  of  this  Station  for  1921, 
page  181. 

Other  Scale  Insects :  There  are  several  other  kinds  of  scales 
which  are  occasionally  troublesome,  such  as  the  scurfy  scale, 
Chionaspis  furfura  Fitch,  on  trees  and  shrubs  of  the  rose  family, 
the  rose  scale,  Aulacaspis  rosae  Bouche  on  roses  and  blackberries, 
the  euonymus  scale,  Chionaspis  euonymi  Comst.,  on  euonymus, 
the  apricot  or  European  fruit  scale,  EulecaniiXm  corni  Bouche,  on 
various  trees  and  shrubs,  and  the  golden  oak  or  pit-making  oak 
scale,  Asferolecanium  variolosum  Ratz.,  on  golden  oak.  Send 
specimens  to  the  Station  for  identification  and  advice  about  treat- 
ment. 

F'or  further  information,  see  Manual  of  Tree  and  Shrub 
Insects. 

Lace  Bugs  and  Leaf  Bugs:  Leaves  of  sycamore  are  com- 
monly attacked  and  somewhat  injured  by  a  lace  bug,  Corythucha 
ciliata  Say,  oak  by  another  species,  Corythucha  arcuata  Sa}^  and 
rhododendron  by  Leptohyrsa  rhododendri  Horv.  Several  kinds 
of  leaf  bugs  of  the  family  Miridae  also  injure  the  leaves  by  suck- 
ing out  the  sap.  As  a  rule  all  of  these  may  be  controlled  by 
spraying  the  under  sides  of  the  leaves  with  nicotine  solution  and 
soap  as  for  aphids. 


FUNGOUS   AND    NON-INFECTIOUS    TROUBLES  171 

FUNGOUS    AND    NON  -  INFECTIOUS    TROUBLES    OF 
ORNAMENTAL  TREES 

G.   P.   CLINTON 

This  article  does  not  include  the  troubles  of  fruit  or  forest 
trees  except  as  grown  for  purely  ornamental  purposes.  Aside 
from  the  injuries  caused  by  insects,  which  are  treated  elsewhere 
in  this  report,  the  other  troubles  of  ornamental  trees  fall  into  two 
classes:  First,  a  variety  of  more  or  less  obscure  troubles,  often 
non-progressive  and  always  non-infectious,  due  to  a  great  variet}^ 
of  causes,  which  we  may  designate  as  "unfavorable  environment." 
Second,  definite  infectious  and  progressive  diseases,  which  are 
caused  by  fungi. 

NON-INFECTIOUS   TROUBLES 

Because  the  agents  are  so  obscure  or  are  present  only  for  a 
short  period,  these  troubles  are  the  hardest  to  identify.  Likewise 
the  symptoms  may  be  so  similar  from  dissimilar  causes,  that,  lack- 
ing both  agent  and  characteristic  symptoms,  one  often  has  to 
give  a  guess  as  to  the  cause.  The  elimination  of  other  possible 
causes  and  extended  observation,  help  to  make  the  guess  of  value. 
In  our  experience  with  ornamental  trees,  we  have  found  injuries 
of  the  following  character :  Winter,  Drought,  Smoke  and  Gas, 
Spray,  Electrical  and  Mechanical. 

Berls,  Knots,  Bunched  Sprouts:  Besides  these  determined 
troubles,  there  occur  on  certain  trees  growths  whose  cause  is  not 
definitely  known.  We  do  not  include  here  the  galls  caused  by 
insects,  whose  nature  is  usually  revealed  by  some  signs  of  larvae 
at  their  center. 

Knots:  On  oak  and  less  frequently  on  hickory,  there  are  occa- 
sionally seen  on  ornamental,  as  well  as  on  forest  trees,  hard, 
roundish,  gall-like  growths  that  vary  in  size  from  an  inch  to  a 
foot  in  diameter.  Usually  several  or  many  of  these  may  occur 
on  a  single  tree,  while  other  trees  of  the  same  variety  in  the 
vicinity  show  no  such  growths.  This  looks  as  if  the  trouble  were 
spreading  over  the  tree.  Its  infectious  nature,  however,  remains 
yet  to  be  proved.  The  resemblance  of  the  smaller  knots  to  crown 
gall  has  caused  some  to  think  that  they  may  be  bacterial  in 
nature.  Whatever  its  cause,  this  trouble  apparently  starts  with 
injury  or  irritation  to  the  cambium  layer,  so  that  it  is  stimulated 
into  great  activity  and  in  such  unusual  directions  as  to  form  a 
gall-like  growth  rather  than  the  natural  woody  layers.  This 
growth,  however,  is  usually  not  so  permanent  as  the  normal 
tissues,  though  many  knots  are  of  considerable  age  as  shown  by 
the  growth  rings.  Where  feasible,  such  growths  may  be  removed 
by  cutting  off  the  branch  some  distance  below  the  growth. 


172  CONNECTICUT   EXPERIMENT    STATION  BULLETIN   263. 

Bunched  Sprouts:  Besides  knots,  certain  trees,  especially 
elms  and  maples,  occasionally  show  bunched  growths  of  fine 
branches  or  unexpanded  buds  on  the  main  trunk.  These  evidently 
come  from  adventitious  buds  developing  because  of  some  hidden 
injury  to  the  tree.  The  writer  suspects  that  winter  injury  is 
often  the  cause.  When  abundant,  they  give  the  main  trunk  a 
somewhat  knotted  or  scraggy  appearance.  Continued  pruning 
will  probably  finally  prevent  their  reappearance. 

Winter  Injuries:  Conditions.  Trees  show  winter  injuries 
under  the  following  conditions.  1.  Some  trees  are  not  hardy, 
being  grown  too  far  north  or  out  of  their  natural  environment. 
There  is  a  demand  for  trees  of  all  sorts  for  ornamental  purposes, 
and  nurserymen  aim  to  supply  the  demand.  Inexperience  at  first 
induced  them  to  grow  semi-tropical  trees  that  were  easily  winter 
injured,  but  now  they  have  largely  cut  out  these  for  their  own 
protection.  However,  there  are  still  grown  a  number  of  species 
that  are  not  entirely  acclimated  and,  of  course,  these  suffer  most. 
2,  A  cultivated  or  fertilized  fruit  tree  is  more  likely  to  suffer 
from  winter  injury  than  a  native  forest  tree.  This  is  partly 
because  the  tissues  make  a  faster,  softer  growth  that  often  does 
not  properly  mature  before  winter  sets  in.  The  ornamental  tree 
occupies  a  position  between  these  two  classes,  as  it  sometimes 
receives  cultivation  or  fertilization  or  both.  3.  Ornamental 
trees  often  stand  by  themselves  and  so  are  more  exposed  to  wintry 
blasts  or,  on  the  other  hand,  they  are  planted  in  sheltered  nooks 
where  they  receive  undesirable  stimulation  during  warm,  sunny, 
winter  days.  4.  Warm  winter  weather  followed  by  sudden 
drops  in  temperature  or  extreme  cold  weather  may  cause  injury 
to  trees  ordinarily  hardy. 

Causes  and  Types.  Winter  injury  takes  place  in  a  variety  of 
ways.  With  trees  grown  for  their  blossoms,  severe  winter 
weather  or  late  spring  frosts  may  destroy  the  blossom  buds. 
Warm,  sunny  weather  of  some  duration  may  start  sap  activity  on 
the  south  or  southwest  side  and  result  in  death  of  the  bark  there, 
so-called  winter  sun-scald,  when  the  temperature  suddenly  drops. 

Cankers  caused  by  killing  the  bark  in  localized  spots,  especially 
at  the  base  of  the  tree,  may  result,  the  latter  type  being  known  as 
collar  girdle.  We  have  seen  elm  trees  in  the  vicinity  of  Stamford 
and  New  Haven  that  showed  cankers  of  varying  size,  small  on  the 
branches  but  a  foot  or  more  on  the  main  trunk  where  they  are 
most  frequent,  for  which  investigators  have  been  unable  so 
far  to  find  any  definite  insect  or  fungous  cause.  The  most  rea- 
sonable supposition,  with  our  present  knowledge,  is  that  these  are 
winter  injuries  where  the  cambium  has  been  killed  in  localized 
spots.     See  Plate  XV,  c. 

We  have  also  been  shown  an  elm  tree,  in  Stamford,  by  the 
head  of  the  F.  A.  Bartlett  Company,  where  the  inner  bark  had 


NON-INFECTIOUS    TROUBLES  173 

been  winter  killed  while  the  cambium  remained  alive,  so  that  a 
new  growth  of  smooth  bark  was  formed  beneath  and  finally 
sloughed  off  the  outer  rough  bark,  thus  presenting  an  unusual 
appearance. 

Sometimes  the  cold  is  severe  enough  to  kill  trees  outright. 
Even  when  the  tree  has  its  w^ood  properly  matured,  if  the  cold 
is  sudden  and  severe,  the  difference  in  temperature  between  the 
inner  and  outer  wood  is  so  great  that  the  contraction  of  the 
tissues  outside  is  faster  than  within,  and  frost  cracks  suddenly 
appear  in  the  bark  or  wood  lengthwise  of  the  tree.  When  healed 
over,  these  often  show  as  ridges  on  the  trunk. 

With  improperly  matured  wood,  wmter  injur}-  may  be  local- 
ized in  the  sap  wood.  If  severe  and  extended  enough  to  kill  it 
prematurely,  the  next  year  the  tree  suffers  from  lack  of  sufficient 
carrying  space  for  the  elaborated  sap,  and  the  tree  makes  a  ver}^ 
slow  growth.  This  injury  shows  through  the  prematurely  dark- 
ened color  of  the  sap  wood,  when  cut  across,  and  is  sometimes 
followed  by  rot  fungi. 

Finally,  the  injury  ma_y  be  localized  in  the  roots,  which  are 
injured  or  killed,  because  of  too  much  moisture  in  the  soil  in  wet 
places  or  because  weakened  by  summer  droughts.  Here  the 
injury  is  usually  hidden  from  view  but  sometimes  can  be  detected 
where  the  exposed  roots  join  the  trunk. 

Drought  and  Heat  Injuries:  Heat,  as  such,  apparently 
causes  very  little  injury  to  trees,  though,  as  a  factor  in  excessive 
transpiration  from  leaves  where  there  is  a  limited  supply  of  water 
to  replace  that  lost,  it  is  indirectly  involved.  When  strong  sun 
light  beats  down  on  the  exposed  south  and  west  sides  of  trees 
recently  transplanted,  and  summer  sun-scald  results,  it  is  probably 
more  directly  a  cause,  though  even  here  the  loss  of  water  is  a 
factor.  Shading  the  trunk  by  V-shaped  boards  on  the  south  side 
lessens  injury  in  such  cases. 

Leaf  Scorch.  Lack  of  moisture  in  the  soil,  injuries  to  the  roots 
or  wood  preventing  the  conveyance  of  water  to  the  leaves,  bright 
sunshine  suddenly  following  rainy  or  muggy  weather,  or 
unusually  hot  days — all  are  factors  in  causing  transpiration  of 
water  from  the  leaves  faster  than  supplied  by  the  roots  with 
resulting  leaf  scorch  troubles.  Whipping  winds,  also  bv  favoring 
transpiration  and  by  mechanically  injuring  the  young  leaves,  are 
often  involved  in  such  troubles.  Hard  maples,  more  than  any 
other  ornamental  trees,  are  subject  to  leaf  scorch  in  this  state, 
and,  as  this  injury  usually  appears  suddenly  and  conspicuously, 
people  often  suspect  it  as  being  a  fungous  injur}\  The  tissues 
of  the  leaves,  especially  at  their  edges,  are  killed  in  an  irregular 
manner  turning  a  reddish  or  brownish  color  and  later  they  are 
often  infested  with  saprophytic  fungi.  They  usually  adhere  to 
the  tree  throughout  the  season,  although  some  may  drop  pre- 


174  CONNECTICUT   EXPERIMENT    STATION  BULLETIN   263. 

maturely.  Sometimes  only  one  tree  of  several  together  may  show 
the  trouble;  this  may  indicate  root  injury.  Again,  trees  may 
show  it  only  on  the  more  exposed  side.  In  the  early  spring  of 
1924,  when  the  injury  was  prominent,  trees  on  the  exposed  hills 
were  the  ones  that  suffered  most.  In  this  case  a  whipping  wind 
was  a  prominent  factor  in  the  injury.  Besides  the  hard,  other 
maples,  elm,  ash,  and  linden  less  frequently  show  leaf  scorch. 
Sometimes  the  pine  needle  blight  is  caused  in  these  ways. 

Scorch  of  Evergreens.  Another  type  of  leaf  scorch  is  that 
shown  on  a  variety  of  evergeens  in  which  the  foliage  is  browned 
and  eventually  killed  on  the  more  exposed  trees,  particularly 
when  young  in  nurseries.  Frequently  this  takes  place  in  late 
winter  or  early  spring  before  growth  has  started,  and  results  from 
warm  days  causing  transpiration  from  the  leaves  when  the 
ground  is  frozen  and  the  tree  cannot  replace  the  water  so  lost. 
Again,  in  severe  winters,  it  may  be  entirely  due  to  the  unusual 
cold  which  partly  kills  the  old  leaves.  Less  frequently  a  very 
late  frost,  after  new  leaves  have  started,  kills  their  exposed  ends 
but  does  not  injure  the  protected  growing  bases,  so  that  the 
leaves  continue  to  grow  but  retain  the  permanently  injured  tips. 
These  troubles  may  be  considered  as  a  purely  winter  or  a  com- 
bination of  winter  and  drought  injury. 

Pine  Needle  Blight.  This  is  a  special  form  of  the  leaf  scorch 
of  evergreens,  and  is  due  to  the  same  causes.  The  white  pine 
is  by  far  the  most  susceptible  species.  The  needles  are  killed 
from  the  tip  inward,  sometimes  for  half  their  length.  If  the 
injury  occurs  early  in  the  season,  the  leaves  are  often  dwarfed 
and  somewhat  bunched.  As  the  leaves  usually  adhere  for  at 
least  two  years,  this  injury  continues  to  be  conspicuous  the  second 
year  and  affects  the  growth  of  the  tree  that  year  as  well.  With 
injury  to  the  new  leaves  the  second  year,  the  trees  not  infre- 
quently die.  Other  trees  lag  along  in  a  sickly  condition  for  a 
number  of  years;  while  those  little  injured,  and  with  vigorous 
roots,  recover  and  show  no  special  signs  of  injury  after  the 
blighted  needles  drop  off'. 

Severe  Summer  Drought  also  may  cause  the  premature  death 
of  the  older  leaves  of  evergreens.  These  leaves,  further  back  on 
the  branches  beyond  the  new  growth,  turn  brown  and  eventually 
drop  off  prematurely.  Before  they  are  shed  the  injury  is  promi- 
nent because  of  the  evident  contrast  between  the  dead  and  living 
leaves  on  the  same  branch.  This  prematuring  and  dropping  of 
the  oldest  living  leaves  is  merely  an  effort  on  the  part  of  the  tree 
to  preserve  the  moisture  for  the  younger  leaves  and  hence  protect 
them  from  injury.  It  was  quite  conspicuous  this  year,  especially 
on  species  of  Arbor-vitae  and  Retinosporas,  and  traced  back,  in 
part,  to  the  very  dry  summer  of  last  year,  as  well  as  to  the  drought 
of  this  vear. 


NON-INFECTIOUS    TROUBLES  175 

Yellow  Leaf  and  Leaf  Fall.  A  type  of  drought  injury  to 
deciduous  trees  is  that  which  takes  place  when  there  is  a  con- 
tinued severe  drought  in  midsummer  or  early  fall.  In  this  case 
the  roots  cannot  supply  sufficient  moisture  for  the  leaves,  with 
the  result  that  those  least  vigorous  and  having  the  most  competi- 
tion for  the  water  drop  off .  Most  leaves  of  a  tree  do  this  gradu- 
ally, often  turning  yellow  before  they  fall,  as  with  the  elm  which 
also  sometimes  sheds  its  young  branches  as  well.  With  the  Nor- 
way maple,  on  the  other  hand,  the  leaves  may  drop  off  while  still 
green.  The  dry  summer  of  1923  caused  more  of  this  trouble 
than  that  of  1924. 

Injured  Rootlets.  Everyone  knows  that  in  transplanting  a 
tree  the  roots  should  not  be  allowed  to  dry  out  too  much.  In 
case  of  severe  drought  this  undoubtedly  takes  place  in  nature, 
with  the  premature  death  of  many  of  the  finer  feeding  rootlets. 
The  direct  injury  though  hidden  from  view  is  shown,  in  part, 
by  the  leaf  fall  to  readjust  the  foliage  and  root  relationships. 
Frequently  the  whole  stor}'-  is  not  told  until  the  succeeding  year, 
when  scantier  foliage  results,  especially  as  shown  in  1924  by  cer- 
tain fruit  trees.  No  doubt,  too,  such  trees  come  through  the 
winter  with  less  vigorous  roots  and  sapwood.  It  is  difficult, 
therefore,  in  some  cases  where  trees  are  backward,  to  determine 
how  much  injury  is  due  to  drought  and  how  much  to  wmter 
injury,  as  both  may  be  involved  even  when  the  winter  is  not 
unusually  severe. 

Smoke  and  Gas  Injuries:  Smokj;  Injury  of  trees  in  this  state 
usually  comes  from  brick  kilns,  though  occasionally  we  have  seen 
injury  from  smoke  stacks  of  factories.  In  any  case,  the  injury 
results  from  sulphur  in  the  coal  that,  on  burning,  escapes  into  the 
air  as  sulphur  dioxide.  Ordinarily  this  does  no  harm,  when  the 
atmospheric  pressure  is  such  that  the  smoke  is  carried  upward, 
but  when  it  drags  along  the  ground  and  the  leaves  are  moistened 
by  rain  or  dew,  this  sulphur  dioxide  is  absorbed  by  the  moisture 
and  apparently  changed  to  sulphurous  or  sulphuric  acid  with 
accompanying  burn  of  the  foliage.  Such  injury  has  occasionally 
occurred  to  the  trees  in  East  Rock  Park  and  near-by  yards  in 
New  Haven,  showing  on  birch,  beech,  elms,  maples,  spruce  and 
other  conifers.  With  the  maple  its  injury  is  similar  to  that  caused 
by  sun  scorch  or  gas.  Such  smoke  injurs^  may  also  affect  other 
vegetation  and  law  suits  have  occasionally  resulted.  The  smoke 
in  railway  yards  from  engines  seems  to  be  more  objectionable 
from  the  soot  settling  on  the  leaves  than  from  actual  burn. 

Gas  Leaks  in  mains  often  cause  injury  to  street  trees.  The 
leak  may  not  always  be  close  to  the  tree,  but  the  gas,  by  following 
the  pipe  escapes  into  the  soil  in  the  vicinity  of  the  roots,  injuring 
or  killing  them.  The  visible  effect  is  shown,  in  time,  by  the 
sickly  appearance  or  death  of  the  leaves.     Hard  maples  seem  to 


176  CONNECTICUT   EXPERIMENT    STATION  BULLETIN   263. 

be  most  subject  to  this  trouble,  and  the  injury  to  these  is  very 
similar  to  that  of  sun  scorch.  This  latter  source  of  injury  should 
be  first  eliminated  as  a  cause.  A  gas  leak  can  usually  be  detected 
only  by  the  odor,  and  is  especially  evident  when  a  hole  is  bored 
into  the  soil  at  a  suspicious  location.  The  gas  is  rarely  or  never 
strong  enough  to  ignite  from  a  match. 

Spray  Injuries:  Occasionally  in  spraying  trees  to  prevent 
insect  or  fungous  troubles,  there  results  more  injury  than  caused 
by  these  agents.  This  is  not  always  the  fault  of  the  person  apply- 
ing the  spray,  as  he  may  be  doing  it  under  conditions  recom- 
mended by  scientific  investigators  and  which  ordinarily  cause 
no  injury. 

Insecticides.  With  these,  where  arsenic  in  some  form  is  gen- 
erally used,  the  poison  is  supposed  to  be  practically  insoluble  and 
so  incapable  of  injury,  but  various  brands,  at  times,  contain  an 
amount  that  is  soluble  beyond  the  danger  point.  Again  the  other 
ingredients,  with  which  the  insecticide  is  combined,  may  raise  the 
solubility  to  this  degree.  For  example,  the  use  of  salt  water 
from  the  Sound  has  been  known  to  increase  the  solubility  of  lead 
arsenate,  and  produce  injury  that  did  not  previously  occur  with 
the  use  of  well  water.  Also  when  mixed  with  fungicides,  the 
combination  of  ingredients  used  sometimes  increases  the  solubility 
of  the  arsenic.  With  certain  of  the  oils  or  emulsions  improperly 
mixed  or  applied,  serious  injury  may  result  even  to  dormant  trees. 

Fungicides.  On  the  other  hand  injury  may  be  directly  due  to 
the  fungicide  as  this  must  be.used  at  a  strength  that  kills,  by  con- 
tact, the  fungus,  but  ought  not  to  be  strong  enough  to  injure  the 
tissues  of  the  leaves.  Sometimes  this  strength  is  beyond  that  of 
safety  to  the  foliage,  especially  of  certain  trees,  and  injury 
results.  Again,  chemical  change,  as  with  Bordeaux  mixture,  may 
occur  after  the  spray  is  put  on  the  foliage ;  or  the  higher  tem- 
perature or  rains,  following  the  treatment,  are  deciding  factors 
that  produce  injury  that  would  not  ordinarily  occur.  Lastly, 
sprays  are  sometimes  applied  that  are  sure  to  cause  more  or  less 
damage  and  should  never  have  been  used;  the  injury  from  this 
source,  however,  is  becoming  less  frequent  because  of  greater 
caution  on  the  part  of  manufacturers  in  trying  out  their  insecti- 
cides and  fungicides  before  placing  them  on  the  market. 

Electrical  Injuries:  Electric  Wires.  The  injury  from  elec- 
trical currents,  either  direct  or  alternating,  of  high  voltage  occurs 
when  the  wire  comes  in  direct  contact  with  the  wet  branches  or 
leaves.  Street  trees  are  the  most  exposed  to  these  conditions. 
Personally,  we  have  seen  very  little  serious  injury  from  this 
cause.  We  have,  however,  observed  street  trees  along  car  lines 
where  an  occasional  branch  or  leaves  or  small  branches  have  been 
killed.  Where  the  feed  wire  ran  through  the  trees  and  its  insula- 
tion had  become  worn,  we  have  seen  maples,  whose  wet  leaves 


NON-INFECTIOUS    TROUBLES  177 

had  blown  in  contact  with  the  wire  at  these  points,  with  locaHzed 
dead  foliage  on  a  considerable  number  of  trees. 

Stone  (Mass.  Agr.  Exp.  Sta.  Bull.  170:  233.)  says;  "When 
strung  too  close  to  trees,  wires  also  often  cause  serious  injury  by 
burning,  sometimes  mechanical  injury  is  done,  and  lightning  dis- 
charges will  cause  harm  when  guy  wires  are  attached  to  trees. 
Both  the  alternating  and  direct  currents  are  used.  They  produce 
different  physiological  effects  on  plant  life,  the  alternating  current 

apparently  being  less  injurious  than  the  direct Most 

of  the  injury  to  trees  from  trolley  or  electric  light  currents  is 
local,  i.e.,  the  injury  takes  place  at  or  near  the  point  of  contact  of 
the  wire  with  the  tree.  This  injury  is  done  in  wet  weather  when 
the  tree  is  covered  with  a  film  of  water  which  provides  favorable 
conditions  for  leakage,  the  current  traversing  the  film  of  water 
on  the  tree  to  the  ground.  The  result  of  the  contact  of  a  wire 
with  a  limb  under  these  conditions  is  a  grounding  of  the  current 
and  burning  of  the  limb,  due  to  'arcing'.  The  vital  layer  and 
wood  become  injured  at  the  point  of  contact,  resulting  in  an  ugly 

scar  and  sometimes  the  destruction  of  the  limb  or  leader 

Practically  all  of  the  burning  of  trees  from  either  alternating  or 
direct  currents  occurs  in  this  way,  since  the  high  electrical  resist- 
ance characteristic  of  trees  does  not  permit  injurious  currents 
to  pass  through  their  tissues." 

There  were  occasional  cases,  however,  where  Dr.  Stone  found 
that  large  trees  had  been  killed  when  the  wire  in  contact,  contrary 
to  the  usual  custom,  carried  the  negative  current  and  the  rails  the 
positive.  This  resulted  in  a  girdling  of  the  tree  near  the  base 
and  its  subsequent  death.  Professor  Tourney  claims  that  injury 
to  the  trees  may,  in  part,  be  due  to  copper  and  zinc  compounds 
carried  from  the  corroded  wires  into  the  tissues  so  injured. 

Lighting  Injuries  are  said  to  be  of  two  types,  the  most  com- 
mon one  is  where  the  tree  is  struck  directly  and  the  injury  is 
entirely  mechanical,  splitting  open  the  wood  and  breaking  loose 
the  bark  or  breaking  oft'  large  limbs.  Such  a  tree  remains  other- 
wise entirely  normal  and  may  live  indefinitely,  if  the  mechanical 
injury  has  not  been  too  severe  or  opens  the  way  to  further  injury 
by  other  agents.  Plate  XV,  d,  shows  a  large  white  pine  at  Corn- 
wall, Conn.,  that  was  injured  in  the  fall  of  1917  but  is  still  living. 

On  the  other  hand  trees  when  struck  are  occasionally  so  badly 
injured,  apparently  in  the  cambium  layer,  without  much  evident 
mechanical  injury  that  death  results  immediately  or  in  a  short 
time.  We  have  seen  white  pine  trees,  dead  and  dying,  where  we 
could  find  no  other  evident  cause.  Mr.  Stoddard,  of  this  depart- 
ment, records  a  case  of  an  oak  shade  tree  at  Litchfield,  that  was 
struck,  and  the  leaves  were  immediately  killed,  the  tree  soon 
dying  without  evident  mechanical  injury. 

In  a  few  cases  we  have  heard  of  shade  trees  on  which,  after 
a  storm,  the  leaves,  or  part  of  them,  suddenly  died  while  still 


178  CONNECTICUT    EXPERIMENT    STATION  BULLETIN   263. 

green.  In  these  cases  it  is  possible  that  the  injury  was  the  result 
of  earth  discharges  as  reported  by  Stone.  He  says :  "These  dis- 
charges occur  during  thunder  storms,  and  those  who  have 
observed  them  for  many  years  relate  that  they  give  rise  to  a  dull, 
characteristic  report  resembling  that  caused  by  throwing  a  wet 
cloth  on  a  hard  surface.  The  whole  tree  is  not  affected  as  a  rule, 
as  the  lightning  stroke  seldom  follows  up  the  main  trunk,  but 
discharges  at  the  point  of  several  branches.  As  a  rule,  however, 
one  side  of  the  trunk  and  one  or  more  of  the  limbs  on  that  side 
are  affected  and  the  symmetry  of  the  tree  destroyed.  The  first 
indication  of  the  discharge  is  shown  by  the  immediate  wilting  and 
subsequent  death  of  the  leaves  of  the  aft'ected  limbs,  which  also 
die  later.  In  the  course  of  time  cracks  similar  to  those  caused 
by  frost,  and  later  ridges  due  to  healing,  will  be  seen  on  the  trunk, 
showing  the  path  of  the  discharge,  and  occasionally,  when  the 
injury  is  considerable,  the  bark  near  the  affected  part  of  the  tree 
falls  off.  The  limbs,  however,  are  not  always  killed,  frequently 
splitting  and  a  cracking  of  the  wood  for  some  depth  is  now  and 
then  observed  on  the  trunk  and  limbs  along  the  path  of  dis- 
charge." 

Mechanical  Injuries:  Besides  the  special  t3-pes  of  mechanical 
injuries  already  mentioned,  these  may  be  caused  in  a  variety  of 
other  ways,  such  as  by  Itail,  ice  and  wind  storms  and  by  animals, 
of  which  mice,  horses  and  men  are  the  chief  offenders. 

Hail  Injury  on  fruit  trees  is  frequently  conspicuous,  but  appar- 
ently shade  trees  suft'er  less  because  of  their  more  hardy  bark. 
On  July  17th  of  the  present  year,  one  of  the  most  severe  hail 
storms  of  recent  years  caused  great  harm  to  the  fruit  trees  in  the 
vicinity  of  Wallingford,  and  less  costly,  though  evident,  injury  to 
the  shade  trees.  A  severe  wind  greatly  exaggerated  the  injury, 
as  the  large  hail  stones  struck  with  great  force.  On  one  small 
apple  tree  less  than  10  feet  high,  we  counted  over  450  distinct 
bruises  on  the  trunk  and  limbs.  Many  of  these  showed  the  bark 
killed,  drying  up  or  sloughing  off  in  time,  and  there  resulted 
small  canker-like  areas.  Later  the  injury  was  partly  obscured 
by  callus  healing  of  the  bark,  so  that  eventually  much  of  the 
injury  will  disappear  or  show  merely  in  irregular  growth  at  these 
points.  The  chief  injury  of  course  was  the  severe  marring  of  the 
fruit,  also  opening  the  way  for  various  rots,  so  that  it  was  of 
little  or  no  value. 

Among  the  shade  trees  showing  evident  injury  were  red  and 
hard  maples,  ash,  sycamore,  hickory,  wild  cherry  and  elm.  The 
cankers  were  most  evident,  of  course,  on  the  smaller  more  tender 
branches  with  smooth  bark,  but  could  also  be  seen  on  limbs  sev- 
eral inches  in  diameter.  They  were  almost  always  longer  length- 
wise of  the  twigs  and  varied  from  one-half  to  one  and  a  half 
inches  long  by  a  quarter  to  half  an  inch  wide.  Specimens  collected 


NON-INFECTIOUS    TROUBLES  179 

late  in  the  fall  by  Mr.  Stoddard  showed  most  of  the  cankers  com- 
pletely healed  over. 

Ice  Injury  results  chiefly  from  the  breakage  due  to  the  unusual 
weight  of  the  ice  which  is  often  many  times  that  of  the  weight 
of  the  branch  which  is  encompassed  especially  on  the  smaller 
twigs.  Mr.  Zappe  of  this  Station  records  a  case  in  the  New 
Haven  storm,  referred  to  later,  where  the  ice  was  30  times  that 
of  the  branch.  Whether  injury  also  results  from  the  freezing 
of  the  sleet  on  the  twigs  is  doubtful,  though  injury  of  this  kind, 
especially  to  evergreens  or  tender  deciduous  trees,  might  result. 
Some  believe  that  the  ice  acts  as  a  lens  in  strong  sunlight  and 
burning  of  the  enclosed  tissues  results.  If  any  heating  or  stimu- 
lation of  the  tissues  occurs,  the  injury  probably  results  from  the 
later  freezing  at  night.  It  is  also  uncertain  whether  the  cold  of 
the  icy  coating  causes  any  more  harm  than  the  dry  cold  on  the 
uncoated  branches. 

The  severe  ice  storm  early  in  February,  1924,  caused  unusual 
damage  to  ornamental  trees  in  the  southern  part  of  the  state, 
especially  in  the  vicinity  of  New  Haven.  The  ice  in  this  case 
stayed  on  the  limbs  for  nearly  a  week.  In  the  early  winter  of 
1921,  a  severe  ice  storm  occurred  in  northern  Connecticut  and 
Massachusetts,  and  caused  unprecedented  injury  to  shade  trees, 
besides  great  damage  to  fruit  trees  and  especially  to  telephone, 
telegraph  and  electric  wires.  The  financial  burden  to  the  towns 
just  in  clearing  up  the  rubbish  from  the  trees  and  on  the  streets 
was  very  heavy.  Some  idea  of  the  damage  wrought  by  this  storm 
is  shown  by  the  photograph,  in  Plate  X,  a,  which  was  taken  near 
Pomfret,  Conn. 

Wind  Injury  is  common  with  most  storms,  breaking  off  the 
dead  branches  and  those  weakened  from  disease  first.  With  very 
severe  stonns,  large  branches  of  the  healthy  but  unprotected  or 
soft  wooded  trees  are  blown  down.  The  worst  injury  occurs 
when  the  heavy  wind  accompanies  an  ice  storm.  The  wreckage 
from  the  ice  storm  at  New  Haven  in  1924,  while  great,  was  much 
less  than  it  would  have  been  had  a  strong  wind  occurred  during 
the  five  or  six  days  that  the  ice  was  on  the  trees.     ( See  Plate  IX. ) 

Animal  Injury  is  most  common  on  street  trees.  The  gnawing 
of  the  bark  by  horses  hitched  near  the  trees  used  to  be  a  very  com- 
mon occurrence,  and  there  are  still  in  evidence  large  canker-like 
areas  on  many  of  our  street  trees  caused  by  the  repeated  injuries 
they  have  received  in  the  past.  Now  the  automobile  seems  to 
have  replaced  the  horse  somewhat  as  a  cause  of  barking  trees. 
Injury  by  mice,  especially  at  the  base  when  long  covered  by  snow 
in  winter,  occurs  prominently  in  some  years,  but  not  in  well  kept 
yards.  In  orchards,  nurseries  or  isolated  places  along  the  road- 
side it  is  not  infrequent  and  may  be  quite  severe. 

Of  all  the  animals,  man  leads  in  the  mechanical  injuries  he 


180  CONNECTICUT    EXPERIMENT    STATION  BULLETIN    263, 

inflicts  on  trees.  The  cutting  off  of  branches  to  allow  passage  of 
telephone  and  electric  wires  is  a  common  occurrence,  but  not 
nearly  so  obnoxious  as  formerly  because  done  in  a  more  scientific 
manner.  Changing  the  soil  level,  cutting  off  interfering  roots  for 
laying  walks  and  pavements,  and  grading  and  digging  for  lawns 
and  buildings  are  other  common  causes  of  injury.  Improperly 
moving  and  transplanting  large  trees  also  often  results  in  a  sicicly 
growth  or  their  final  death. 

Bleeding,  Sour  Sap,  Slimy  Flux:  Bleeding  usually  results 
from  some  mechanical  injury  but  under  ordinary  conditions  stops 
of  itself.  This  was  the  case  with  the  maples  following  the  recent 
ice  storm  in  New  Haven,  as  the  injury  occurred  about  the  time 
active  sap  fiow  was  starting.  The  dripping  from  the  broken  twigs 
occasionally  formed  icicles  during  the  night,  or  frequently  made 
a  wet  spot  on  the  sidewalk  that  was  still  evident  long  after  it 
dried  out.  Of  course  some  food,  as  sugar,  etc.,  was  lost  to  the 
trees  in  this  way,  but  this  injury  was  negligible. 

Bleeding  may  also  start  as  a  result  of  pruning  or  cavity  work 
and  in  the  elm,  from  whatever  cause,  it  is  sometimes  very  difficult 
to  stop.  The  loss  of  the  water  or  sap,  while  undesirable,  is  not 
the  evident  evil  here.  The  food  in  the  sap  affords  a  fine  oppor- 
tunity for  the  development  of  bacteria  and  Sour  Sap  results.  This 
leakage  may  in  time  become  a  soft  slime  through  the  presence  of 
both  bacteria  and  yeast  fungi.  Good  examples  of  this,  as  Slimy 
Flux,  can  be  seen  on  the  stumps  of  yellow  birch  that  are  cut  in 
late  winter  or  early  spring.  In  any  case,  this  infected  sap,  cover- 
ing the  healthy  bark,  is  likely  in  time  to  kill  the  cambium  and 
decay  of  the  bark  results.  Leakage  is  frequently  prevented  or 
stopped  by  searing  over  the  exposed  sap  wood  with  a  hot  iron. 
Again  the  drip  is  sometimes  successfully  carried  away  from  the 
bark  by  a  protruding  iron  pipe  in  the  filling.  There  are  cases,  how- 
ever, where  bleeding  and  injury  result  despite  all  precautions. 

Treatments:  Watering.  For  all  of  these  injuries  spraying,  of 
course,  is  of  no  value.  With  valuable  trees  where  drought  is 
long  and  severe,  watering  is  helpful.  This  must  be  kept  up,  how- 
ever, until  the  danger  is  past.  It  should  not  be  of  the  frequent 
sprinkling  type,  as  given  to  lawns,  but  rather  an  occasional  good 
soaking  in  which  the  water  penetrates  deep  into  the  soil.  This 
may  be  aided  by  drill  holes  aroimd  the  trees  in  which  the  hose 
is  inserted. 

Fertilizing.  Where  injury  is  manifest  but  the  tree  is  still  vig- 
orous enough  to  save,  whether  the  injury  is  due  to  drought  or 
winter,  fertilization,  especially  of  deciduous  trees,  may  be 
employed.  One  must  use  care,  however,  that  this  is  given  early 
enough  in  the  season  so  that  the  tree  may  property  mature  its 
wood  and  buds  before  winter  sets  in.  Manure  can  be  used  with 
less  impunity  in  this  respect  than  most  chemical  fertilizers.     The 


FUNGOUS   DISEASES  181 

quickest  action  is  obtained  with  the  use  of  nitrate  of  soda;  this 
can  be  placed  in  drill  holes  in  the  ground,  about  10  feet  apart 
Avith  large  trees,  around  the  spread  of  the  branches  and  washed 
in  with  a  hose.  From  one  to  10  pounds,  according  to  the  size 
of  the  tree,  may  be  used.  A  complete  fertilizer  scattered  broad- 
cast over  the  ground  is  sometimes  used  to  increase  the  general 
vigor  of  the  tree.  Dr.  Jenkins  has  recommended,  in  the  past,  the 
following:  Nitrate  of  soda,  acid  phosphate  and  muriate  of  potash, 
each  five  parts  by  weight,  to  be  mixed  not  more  than  a  week 
before  using  and  to  be  spread  broadcast,  one-half  pound  to  each 
50  square  feet  of  ground,  in  two  applications  one  month  apart  in 
the  spring. 

Pruning,  etc.  With  the  preceding  tree  injuries,  of  course,  one 
of  the  first  treatments  consists  in  removing  seriously  injured  and 
dead  branches,  and  protecting  the  cut  and  exposed  surfaces.  The 
trimming  should  be  done  with  reference  to  preserving  or  renew- 
ing the  symmetry  of  the  tree.  Bark  loosened  but  not  torn  off 
may  sometimes  be  grown  back  by  nailing  to  the  tree,  if  done 
immediately  and  protected  from  drjdng  out.  If  dead  it  should  be 
cut  back  to  the  living  tissues  to  prevent  decay  and  to  favor  proper 
callus  formation.  Sometimes  cavity  work  may  be  necessary, 
especially  later  if  wood   rot  starts. 

FUNGOUS   DISEASES 

While  the  injuries  caused  by  fungi  may  be  as  conspicuous  as 
those  caused  by  insects,  nevertheless,  the  general  public  is  not  so 
often  microscopic  in  size,  and  usually  not  readily  differentiated 
well  acquainted  with  their  causal  agents,  since  the  fungus  is 
from  the  injury  itself.  They  have,  on  the  other  hand,  this  advan- 
tage to  the  scientist — the}'  do  not  fly  away  after  causing  the  injury 
but  stay  there  permanently,  though  they  are  not  alwa3^s  easily 
determined  individually  because  the  fruiting  stage  is  often  late 
in  maturing.  To  understand  fungi  and  the  injury  they  cause, 
it  is  desirable  to  know  something  of  their  general,  as  well  as  their 
specific,  nature.  We  give  this  information  briefly  in  the  follow- 
ing paragraphs : 

Nature.  Fungi  are  the  lowest  forms  of  plant  life.  They  differ 
from  all  other  plants  in  lacking  the  green  coloring  matter,  char- 
acteristic of  leaves  known  as  chlorophyll.  Lacking  this  they 
cannot  manufacture  from  water,  gases  and  the  chemical  con- 
stituents of  the  soil,  their  food.  This  they  must  obtain  in  an 
organized  form  from  products  of  living  or  dead  plants  or  animals. 
If  from  the  living,  they  produce  disease  as  a  result  and  are  called 
parasites ;  if  from  the  dead,  they  merely  produce  decay  and  are 
called  saprophytes.  With  wood  destroying  fungi  decay  of  the 
dead  heart  wood  by  a  saprophytic  fungus  may,  by  weakening  the 


182  CONNECTICUT   EXPERIMENT   STATION  BULLETIN   263. 

strength  of  the  trunk  or  roots,  be  indirectly  responsible  for  more 
injury  than  the  parasitic  form  that  directly  attacks  the  living 
tissues. 

Stages.  Fungi  consist  of  two  stages,  a  vegetative  stage  that 
has  to  do  with  gathering  their  food,  and  spore  stages  that  perpetu- 
ate their  existence  the  same  as  the  seeds  do  the  flowering  plants. 
The  vegetative  stage  is  usually  inconspicuous  and  often  not  visible 
to  the  naked  eye,  as  it  consists  of  microscopic  branched  threads  that 
ramify  through  the  substratum  or  host,  on  which  it  occurs,  in 
search  for  food.  There  is  comparatively  little  difference  in  the 
appearance  of  the  vegetative  stage,  or  mycelium,  of  different  fungi, 
hence  the  necessity  of  seeing  the  spore  stages  for  identification. 

The  spores  are  formed  on  or  near  the  surface  of  the  host  and 
are  much  more  conspicuous  and  differentiated  especially  as  seen 
under  the  compound  microscope.  Mushrooms  and  shelf  fungi 
are  the  largest  fruiting  forms.  Unlike  flowering  plants,  fungi 
may  have  more  than  one  kind  of  spores,  but  only  one  corresponds 
directly  to  the  seed  in  that  it  is  the  result  of  fertilization  of  the 
sexual  elements,  the  other  kinds  being  of  an  asexual  nature  such 
as  buds,  tubers,  runners,  etc.,  in  plants.  Some  spores  are  tempo- 
rary and  are  merely  useful  in  quickly  spreading  the  fungus  over 
the  host  or  to  new  ones.  Other  spores  are  more  hardy  and  serve 
to  carry  the  fungus  over  unfavorable  periods,  such  as  winter. 
With  the  rusts,  not  infrequently,  certain  spore  stages  occur  as 
parasites  on  one  host  and  others  on  an  entirely  different  host 
species,  thus  greatly  complicating  the  life  history  of  the  fungus. 

Infection.  In  any  case  the  spores  give  rise  to  new  individuals 
by  germinating  into  threads  that  by  later  growth  form  the 
mycelium.  With  parasitic  forms  this  germ  tube  or  thread  must 
penetrate  in  some  manner  into  the  living  tissues  in  order  to  gain 
the  food  necessary  for  its  growth.  All  preventive  treatments  of 
fungous  diseases  by  spraying  are  based  on  killing  the  spores  that 
are  carried  to  the  susceptible  parts  of  the  plants  before  they  can 
gain  entrance  by  their  germ  tubes  into  the  tissues.  Once  inside, 
the  mycelium  is  no  more  injured  by  the  spray  than  the  plant 
tissues  on  which  it  is  placed.  This  makes  it  necessary  to  protect 
the  tissues  by  repeated  and  thorough  spraying  as  long  as  there  is 
danger  of  the  fungus  gaining  entrance.  It  also  means  that  the 
fungicide  must  be  able  to  kill  the  spores  or  their  germ  tubes  but 
cause  no  injury  to  the  plant  tissues. 

LEAF  AND  BARK  FUNGI 

We  may  include  most  of  the  parasitic  fungi  of  trees  with  those 
that  cause  injury  to  the  leaves  or  the  bark.  They  are  numerous 
and  of  great  variety.  Quite  frequently  each  species  is  limited 
to  a  single  kind  of  tree  or  its  verv  close  relatives.     Usuallv  the 


LEAF  AND  BARK  FUNGI  183 

earlier  spore  stages  are  parasitic  while  the  later  ones  merely  occur 
as  saprophytes  on  the  dead  or  dying  tissues.  We  can  best  con- 
sider them  here,  grouped  semi-scientifically,  under  the  following 
headings:  Anthracnoses,  Leaf  Spots,  Leaf  Curls,  Powdery  Mil- 
dews, Rusts,  Blights  and  Cankers. 

Anthracnoses :  This  is  a  general  term  applied  to  certain  genera 
of  fungi  that  locally  kill  the  tissues  of  the  leaf  or  the  twig  and 
ooze  out  their  spores  as  inconspicuous,  sticky  drops  on  the  surface 
of  the  host.  The  more  common  ones  met  with  so  far  in  this  state 
are  as  follows : 

Ash  Anthracnose,  Gloeosporium  aridum  Ell.  &  Holw.,  in  wet 
years,  especially  along  the  coast,  has  caused  considerable  injury 
to  the  white  ash  foliage,  large  areas  withering  up  or  turning  a 
light  brown  color. 

Maple  Anthracnose,  Gloeosporium  saccharini  Ell.  &  Ev.,  is 
most  likely  to  show  on  the  sugar  maple,  but  only  occasionally 
causes  conspicuous  injury.  It  is  so  similar  to  the  leaf  scorch  of 
this  tree  that  one  usually  has  to  examine  the  leaves  microscopi- 
cally for  the  spores  before  he  can  be  sure  of  the  real  cause. 

Oak  Anthracnose,  Gloeosporium  canadense  Ell.  &  Ev.,  was 
unusually  conspicuous  last  spring  on  white  oaks,  but,  partly 
because  it  does  not  carr)--  over  so  abundantly  on  the  twigs,  the 
injury  is  less  evident  than  that  of  the  sycamore.  Fewer  leaves 
are  killed  in  the  bud,  and  the  injurs'  is  more  localized  as  light 
brown  dead  areas  on  the  mature  leaves. 

Sycamore  Anthracnose,  Gloeosporium  nervisequuiii  (Fckl.) 
Sacc,  derives  its  specific  name  from  the  fact  that  it  seems  to  pre- 
fer the  tissue  of  the  leaf  along  the  main  veins.  It  develops  early 
in  the  season,  often  as  soon  as  the  buds  begin  to  unfold,  with  the 
result  that  many  of  the  leaves  fail  to  develop.  It  can  do  this 
because  its  spores  develop  first  on  the  young  branches  and 
are  washed  into  the  opening  buds.  The  injury  was  the  most 
severe  in  the  spring  of  1924  that  we  have  ever  seen.  Some  trees 
had  all  their  very  young  leaves  killed  and  had  to  develop  a  new 
crop,  which,  of  course,  resulted  in  a  scanty  foliage  all  summer. 
When  seen  at  first  it  looked  as  if  the  trees  were  dead  or  doomed 
to  die,  but  sycamores  can  stand  a  lot  of  such  punishment  and 
still  survive.  However,  they  usually  look  in  this  state  as  if  half 
winter  killed,  because  of  repeated  attacks.  The  European  syca- 
more is  much  less  susceptible  to  injury  than  the  American. 

Other  Anthracnoses,  of  a  less  conspicuous  nature,  are  those 
occasionally  occurring  on  hickory,  Gloeosporium  Caryae  Ell.  & 
Dearn. ;  Linden,  Gloerisporium  Tiliae  Oud. ;  Poplar,  Marsonia 
Castagnei  (Desm.  &  Mont.)  Sacc;  Butternut  and  Walnut, 
Marsonia  Juglandis  (Lib.)  Sacc.  We  even  found  an  unusual 
one,  more  or  less  conspicuous  the  past  year,  on  Beech,  Gloeo- 
sporium Fagi  var.  Americana  Ell.  &  Ev. 


184  CONNECTICUT    EXPERIMENT    STATION  BULLETIN   263. 

Leaf  Spots:  These  are  injuries  of  leaves  very  similar  to  the 
Anthracnoses,  usually  showing  as  small,  circular  or  angular,  dead 
spots,  varying  in  color  but  occasionally  occupying  areas  of  con- 
siderable extent.  They  are  caused  by  a  great  variety  of  micro- 
scopic fungi  whose  fruiting  stages  may  show  as  inconspicuous 
pustules  imbedded  in  the  injured  or  dead  tissues  or  as  a  moldy 
growth  on  the  surface. 

Ash  Leaf  Spot  or  Speck,  Piggotia  Fraxini  Berk.  &  Cke.,  shows 
as  small  purplish  specks  on  the  upper  surface  of  the  leaves  with 
the  fruiting  stage  of  the  fungus  rather  prominently  scattered  over 
the  lower  surface  as  small  black  pustules.  It  is  not  a  very 
important  parasite.  There  are  several  other  fungi  that  cause 
more  definite  leaf  spots  of  the  ash  but  are  infrequently  seen  here. 

Box  Elder  Leaf  Spot,  Phyllosticia  minima  (Berk.  &  Cke.) 
Ell.,  appears  as  grayish  or  reddish-brown  circular  spots,  a  quar- 
ter of  an  inch  or  so  in  diameter,  with  minute,  black,  fruiting 
pustules  imbedded  in  the  center.  This  leaf  spot  is  identical  with 
or  very  closely  related  to  similar  spots  on  leaves  of  various 
maples,  P.  acericola  Cke.  &  Ell.  On  the  latter,  in  some  seasons, 
it  is  quite  prominent  and  has  been  complained  of  as  causing 
marked  injury. 

Catalpa  Leaf  Spot,  Macrosporium  Catalpae  Ell.  &  Mart., 
shows  in  certain  seasons  as  definite,  rounded,  reddish-brown  spots 
an  inch  or  less  in  diameter  appearing  suddenly  on  the  new  leaves, 
often  rather  abundantly,  so  that  partial  defoliation  results.  Simi- 
lar spots  are  said  to  be  caused  by  another  fungus,  Phyllosticia 
Catalpae  Ell.  &  Mart.,  but  while  we  have  found  one  or  the  other 
occasionally  present,  more  frequently  a  definite  fruiting  stage  is 
absent  and  we  still  are  in  doubt  as  to  the  real  cause.  The  Japanese 
catalpa  apparently  is  most  frequently  attacked.  Whether  spray- 
ing will  prove  of  value  remains  yet  to  be  demonstrated. 

Chestnut  Leaf  Spot,  Septoria  ochroleuca  Berk.  &  Cke.,  is 
usually  very  evident  as  numerous,  grayish,  circular  spots  with  a 
purplish  border  about  a  quarter  of  an  inch  in  diameter.  The 
fruiting  bodies  are  more  evident  beneath  as  small,  embedded, 
blackish  specks.  This  trouble,  on  account  of  the  rarity  of  its 
host  as  a  shade  or  forest  tree,  is  now  seen  only  occasionally  on 
sprout  growth. 

Ehn  Leaf  Spot,  Dothidella  ulmea  (Schw.)  Ell.  &  Ev.,  known 
also  as  Gnomonia  ulmea  (Schw.)  Thuem.,  forms  minute  black 
eruptions,  somewhat  clustered  together  in  small  circles  or  scat- 
tered over  the  whole  upper  surface  of  the  living  leaves.  In  time 
there  is  a  whitish  or  grayish  margin  around  these  groups,  due  to 
the  wearing  away  of  the  epidermis.  The  fungus  matures  its  spore 
stage  on  the  old  leaves  on  the  ground  in  spring,  its  fruiting 
perithecia  opening  on  the  lower  surface.    When  severe,  more  or 


LEAF   AND    BARK   FUNGI  185 

less  defoliation  in  midsummer  takes  place.  Occasionally  it  is 
quite  bad,  and  it  is  usually  present  in  a  small  way  every  year. 
Burning  the  leaves  in  the  fall  is  desirable. 

Hawthorn  Leaf  Spot,  Entomosporium  Thuemenii  (Cke.) 
Sacc,  appears  as  very  small,  angular,  reddish-brown  spots  most 
frequently  on  the  English  hawthorn,  grown  occasionally  in  yards. 
It  has  been  sent  in  for  identification  a  few  times  as  it  causes  some 
defoliation  where  bad. 

Horsechestnut  Leaf  Spot,  Phyllosticta  Paviae  Desm.,  seems  to 
occur  largely  on  the  European  species  commonly  grown  in  this 
state.  Some  years,  like  1922,  it  is  very  injurious  and  again,  like 
the  present  dry  year,  comparatively  mconspicuous.  It  is  one  of 
the  most  injurious  of  our  leaf  spot  diseases  of  trees,  since  the 
reddish-brown  dead  areas  often  cover  a  considerable  part  of  the 
leaves.  Most  of  the  leaves  of  the  tree  are  infected  and  early 
defoliation  occurs.  It  looks  very  much  like  a  sun  scorch.  The 
tree  itself  does  not  seem  to  be  so  seriously  injured  as  might  be 
expected,  since  the  next  year  it  usually  starts  out  with  a  full  crop 
of  leaves.  Besides  spraymg  with  Bordeaux,  raking  up  and  burn- 
ing the  leaves  is  desirable. 

Maple  Tar  or  Black  Spot,  Rhytisma  acerinnin  (Pers.)  Fr.,  as 
its  name  indicates,  shows  as  a  black  spot  on  the  upper  surface  of 
the  leaf  much  resembling  a  finger  print.  The  tissues  involved  are 
somewhat  thickened  and  slightly  raised  above  and  are  concave 
and  lighter  colored  below.  Many  of  these  spots  are  often 
crowded  on  the  leaf.  An  inconspicuous  summer  spore  stage  is 
said  to  develop  in  these  spots  but  the  mature  stage  does  not  appear 
imtil  the  following  spring,  on  the  dead  leaves  on  the  ground. 
Soft  maples,  especially  the  cut-leaf  form,  are  especially  subject 
to  attack.  The  fungus  also  is  common  on  the  red  maple.  Burn- 
ing the  leaves  in  the  fall,  or  when  they  drop  prematurely,  is 
recommended. 

Leaf  Curls:  These  produce  a  thickening  of  the  leaf  tissue, 
together  with  a  cupping  or  other  slight  distortion,  and,  occa- 
sionally when  involving  buds  or  fruits,  form  a  bag-like  enlarge- 
ment. They  are  found  chiefly  on  fruit  and  forest  trees.  The 
infected  tissues  are  often  whitish  or  flesh  colored. 

Oak  Leaf  Curl,  Taphrina  caerulescens  (Desm.  &  Mont.)  Tul., 
is  about  the  only  conspicuous  form  occurring  on  ornamental  trees, 
where  we  have  noticed  it  common  the  past  few  years.  It  pro- 
duces a  cupped  thickening  of  the  leaf  tissues  an  inch  or  less  across, 
often  several  occurring  closely  placed  over  the  leaf.  The  upper 
surface  is  light  colored  while  the  lower  reveals  a  grayish-purple 
growth  of  the  fruiting  stage.  The  same  tree  often  shows  the 
trouble  year  after  year,  indicating  that  it  might  be  carried  over 
on  the  young  branches  though  it  is  said  not  to  be  perennial.    Here 


186  CONNECTICUT    EXPERIMENT    STATION  BULLETIN    263. 

is  another  case  where  burning  the  fallen  leaves  might  prove  help- 
ful. A  related  species,  occasionally  found  on  the  elm,  is  Taphrina 
Uhm  (Fckl.)  Joh. 

Powdery  Mildews:  These  differ  from  most  of  the  other  dis- 
ease producing  fungi  in  that  almost  all  of  their  mycelium,  as 
well  as  their  fruiting  stages,  is  exposed  on  the  surfaces  of  the 
tissues,  only  short  sucker-like  threads  penetrating  these  to  extract 
the  food  necessary  for  growth.  They  consequently  form  a  whit- 
ish cobweb-like  growth  more  or  less  evident  to  the  naked  eye. 
The  small  blackened  dots  embedded  in  this  growth  are  the  mature 
fruiting  bodies,  or  perithecia.  Under  the  microscope  these  show 
numerous  appendages  radiating  out  from  the  central  spore  case. 
Quite  a  few  trees,  as  well  as  shrubs  and  herbaceous  plants,  are 
attacked  by  these  mildews,  chiefly  on  the  leaves,  but  rarely  serious 
injury  results  to  the  ornamental  trees.  The  following  may  be 
briefly  listed: 

Catalpa  Powdery  Mildew,  Microsphaera  elevata  Burr.,  is  con- 
sidered by  some  as  not  distinct  from  that  on  oak  or  chestnut.  It 
shows  as  a  rather  inconspicuous  whitish  growth,  most  com- 
monly on  the  upper  surface  of  the  leaves. 

Chestnut,  Oak,  Powdery  Mildew,  Microsphaera  alni  (Wallr.) 
VVint.,  attacks  a  wide  variety  of  trees  and  shrubs,  both  cultivated 
and  wild.  Usually  there  is  a  conspicuous,  cobweb-like  coating, 
most  frequently  on  the  upper  surface  of  the  leaf,  and  in  this  are 
finally  seen  the  numerous,  small,  black,  spore-bearing  receptacles. 

Maple,  etc..  Powdery  Mildews:  Uncimda  circinata  Cke.  & 
Pk.,  on  the  hard  maples,  usually  forms  a  rather  inconspicuous 
mycelial  growth  in  spots  on  the  leaves,  with  few  perithecia; 
U.  Uexuosa  Pk.,  on  horsechestnuts,  has  a  similar  but  more  general 
growth  over  the  whole  leaf  surface;  while  U.  Salicis  (D.C.) 
Wint.,  on  willows,  is  apt  to  be  very  evident  and  with  a  great 
abundance  of  perithecia.  All  these  species,  as  the  generic  name 
(Uncinula)  indicates,  have  appendages  hooked  at  the  end. 

Rusts:  These  are  the  most  interesting  and  destructive  of  all 
fungi  because  of  their  several  spore  stages,  some  of  which  occur 
on  entirely  different  hosts,  and  because  in  all  stages  they  are  strict 
parasites.  They  usually  form  dusty,  erumpent,  small  pustules, 
more  or  less  thickly  scattered  over  the  infected  tissues.  The 
earlier  spore  stages  are  generally  a  yellow  or  orange  color,  and 
the  later  a  red-  or  black-brown.  Seen  by  the  naked  eye,  they  are 
not  apt  to  be  confused  with  any  other  fungi,  except  the  smuts 
which  do  not  occur  on  trees.  Not  only  do  the  rusts  cause  serious 
injury  to  trees,  but  they  are  among  the  most  destructive  parasites 
of  all  kinds  of  plants,  particularly  the  cereals.  Because  the  differ- 
ent stages  frequently  inhabit  different  hosts  and  their  relationships 
were  or  are  not  known,  scientific  names  have  been  sfiven  to  the 


LEAF   AND    BARK   FUNGI  187 

earlier  or  immature  stages  that  apply  only  to  them,  while  the  name 
given  to  the  latest,  or  mature  stage,  not  only  applies  to  it  but  to 
all  of  the  stages.    For  example : 

Ash  Rust,  Aecidium  Fraxini  Schw.,  is  the  early  stage  of  a 
rust  that  has  the  repeating  and  mature  stages,  known  as  Puccinia 
Fraxinata  (Lk.)  Arth.,  on  marsh  grass.  Therefore  the  most 
complaint  of  injury  to  ash  trees  in  this  state  is  in  the  vicinit}'  of 
the  Sound,  where  marsh  grass  is  common.  The  rust  not  only 
attacks  the  leaves,  petioles  and  young  twigs  but  also  the  winged 
fruits  of  the  ash.  It  occurs  in  the  cluster  cup  stage  projecting 
above  the  tissues  as  minute,  aggregated,  toothed  receptacles  filled 
with  orange  colored  spores.  The  infections  give  rise  to  some 
swelling  and  distortion  of  the  invaded  tissues. 

Flowering- Crab  Rust,  Roestelia  pyrata  (Schw.)  Thax.,  is  a 
stage  similar  to  the  preceding,  on  apple  leaves,  but  differs  chiefly 
in  having  the  cluster-cups  fringed  with  hairs  rather  than  toothed. 
Its  niature  stage  occurs  in  the  jelly-like  horns,  formed  during  wet 
spring  weather,  on  the  so-called  "cedar  apples"  of  the  red  cedar. 
The  flowering  crab  is  one  of  the  most  susceptible  hosts  attacked, 
though  the  Wealthy  variety  of  apples  is  about  as  bad. 

Mountain-Ash  Rust,  Roestelia  cornuta  (Pers.)  Fr.,  is  similar 
to  the  apple  rust.  It  is  rarely  found  here  and  has  its  mature  stage 
on  the  juniper. 

Poplar  Rusts :  Melampsora  Medusae  Thuem.  is  not  infrequent 
on  the  Carolina  poplar,  showing,  in  its  repeating  stage,  as  minute 
yellow  pustules  and,  in  its  mature  stage,  as  reddish  blisters,  on 
the  under  surface  of  the  leaves.  Its  earlier  stage  occurs  on  the 
larch.  A  very  similar  rust,  known  as  Melampsora  Ahietis-cana- 
densis  (Farl.)  Ludw.,  occurs  on  the  large  tooth  aspen  and  has  its 
earlier  stage  on  the  cones  and  leaves  of  the  hemlock. 

Willow  Rusts,  Meinvii psora  Biglowii  Thuem.  and  ilf.  ameri- 
cana  Arth.,  are  very  similar  rusts  on  the  leaves  of  these  hosts,  and 
have  their  earlier  stages  on  the  larch  and  balsam. 

White-Pine  Blister  Rust,  Peridermium  Strohi  Kleb.,  is  the 
rust  that  was  accidentally  imported  from  Europe  some  years  ago 
and  against  which  such  united  effort  by  government  and  state 
•officials  has  been  expended  to  prevent  its  further  spread  in  this 
country.  The  stage  on  the  white  pine  is  the  early  one,  showing 
as  conspicuous  white  blisters  that  soon  rupture  and  disclose  the 
orange  powdery  mass  of  spores.  These  carr>'  the  fungus  to  Ribes 
species,  currants  and  gooseberries,  and  form  there  the  later  stages 
known  as  Cronartmm  rihicola  Fisch.  de  Wald.  On  the  latter 
hosts  there  is  formed,  first,  the  repeating  stage,  showing  as  small 
powdery  pustules  whose  spores  spread  the  fungus  on  these  hosts 
during  the  summer  and,  finally,  the  mature  stage,  short  hair- 
like spores  that  carry  the  rust  back  to  the  pine  needles  in  the  fall. 


188  CONNECTICUT    EXPERIMENT    STATION  BULLETIN    263. 

The  injury  to  the  currants  and  gooseberries  is  not  serious, 
though  frequently  causing  defohation,  but  to  the  pine,  because  of 
its  perennial  mycelium,  the  rust  eventually  girdles  the  trunk  or 
branch  and  causes  its  death.  The  disease  is  controlled  on  orna- 
mental trees  by  isolation  from  Ribes  and  by  cutting  off  infected 
branches  some  distance  below  the  infested  place.  In  plantations, 
eradication  of  all  Rihes,  within  and  nearby,  is  advocated.  A 
similar  rust  on  several  two-  and  three-needle  pines,  Feridermium 
Comptoniae  Arth.,  in  this  state,  has  its  mature  stage,  Cronartium 
Comptoniae  Arth.,  on  sweet  fern. 

Other  Rusts,  occurring  on  ornamental  trees  here  but  never 
causing  serious  damage,  are:  Gymnosporangium  Juniperi-vir- 
ginianae  Schw.,  on  cedars,  mature  stage  of  Roestelia  pyrata 
(Schw.)  Thax.,  q.  v.;  Peridermium  acicolnm  Underw.  &  Earle 
and  Peridermium  delicatuhtm  Arth.  &  Kern.,  on  pitch  pine 
needles,  mature  stages  on  goldenrod  and  asters  known  as  species 
of  Coleosporium;  Peridermium  Peckii  Thuem.,  on  leaves  of  hem- 
lock, mature  stag'e  on  huckleberries  and  blueberries  known  as 
Pucciniastrum  Myrtilli  (Schum.)  Arth.;  Caeoma  Ahietis-cana- 
densis  Farl.,  on  leaves  and  cones  of  hemlock,  mature  stage  of 
Melampsora  Abietis-canadensis  (Farl.)  Ludw.,  q.  v. 

Bacterial  Blights  and  Galls:  These  diseases  are  not  com- 
mon on  ornamental  trees,  though  a  number  have  been  found  on 
fruit  trees.  Their  cause,  as  indicated  by  the  above  title,  is  bac- 
teria, the  smallest  of  living  things,  which  are  so  destructive  to 
other  plant  life  and  are  responsible  for  many  of  the  contagious 
diseases  of  animals. 

Crown  Gall,  Psendomonas  iumefaciens  (S.  &  T.)  Stev.,  as  its 
name  indicates,  produces  galls  on  the  trunk  and  roots  and  occa- 
sionally higher  up  on  the  limbs  of  a  great  variety  of  trees,  as  well 
as  of  shrubs  and  herbs.  So  far  we  have  found  it  on  ornamental 
trees  only  on  poplar  and  willow.  The  obvious  treatment  is  to 
cut  ofif  the  infected  limb  some  distance  below  the  gall.  When  on 
the  main  trunk,  cutting  out  the  infected  tissues  is  of  doubtful 
value. 

Mulberry  Blight,  Psendomonas  Mori  (B.  &  L.)  Stev.,  pro- 
duces small,  watery,  reddish-brown  areas  on  the  leaves  and 
cankers  usually  on  the  younger  twigs.     It  is  rarely  met  with. 

Fire  Blight,  Bacillus  am.ylovorus  (Burr.)  De  Toni,  while  com- 
mon on  such  fruit  trees  as  pear,  quince  and  apple,  has  only  been 
seen  once  on  trees  grown  for  ornament.  In  this  case  it  was  quite 
prominent  on  the  English  Hawthorn.  The  young  twigs  are 
killed  back  for  a  foot  or  more,  the  blackened  leaves  still  adhering, 
infection  takes  place  chiefly  at  blossoming  time.  The  bacteria 
are  carried  there  accidentally  by  bees,  etc.,  and  multiplying  in  the 
nectar   of   the   blossoms,    work    downward    through    the    tender 


LEAF    AND    BARK   FUNGI  189 

tissues  of  the  twigs.  More  rarely  large  branches  are  killed 
through  cankers  in  the  bark.  Cutting  off  the  infected  twigs, 
when  dormant,  some  distance  below  the  diseased  tissue  and  wip- 
ing the  pruning  tool  each  time  with  a  cloth  saturated  with  car- 
bolic acid  or  corrosive  sublimate,  to  kill  adhering  germs,  has  been 
the  common  method  for  control. 

Cankers:  When  a  fungus  enters  a  branch  or  trunk  of  a  tree, 
it  usually  becomes  perennial  there  and,  gradually  killing  the  bark, 
makes  a  cankered  _  spot  which,  if  it  encircles  the  branch,  causes 
death  of  the  parts  above.  Fortunately,  few  of  the  fungi  thus 
invade  large  limbs  or  the  main  trunk. 

Chestnut  Blight,  Endothia  parasitica  (Murr.)  Anders.,  is  one 
of  these  canker  fungi  that  has  proved  destructive  in  this  way. 
Its  action  has  been  unique  in  tree  history  in  this  state,  as  it  has 
practically  eradicated  not  only  all  forest  chestnuts  but  ornamental 
ones  as  well.  All  that  are  left  are  the  sprouts  that  come  up  from 
the  cut  trees  and  occasional  small  seedlings,  both  of  which  are 
still  subject  to  attacks.  Treatment  of  any  kind,  so  far,  has  been 
unsuccessful  with  this  disease.  This  and  the  forestry  depart- 
ment, however,  expect  soon  to  start  small  seedling  plantations  for 
future  observation. 

Poplar  Cankers,  Dothichisa  populea  Sacc.  &  Bri.,  is  another, 
apparently  European,  importation  that  has  recently  been  produc- 
ing havoc  with  our  ornamental  poplars,  especially  the  Lombardy. 
Not  all  the  injury,  however,  is  due  to  this  fungus,  as  insects  and 
winter  injury  have  played  their  part.  The  remedy  for  this  trouble 
seems  to  be  to  start  with  a  young  tree  entirely  free  from  the  dis- 
ease, as  we  have  seen  large  isolated  trees  that  continue  to  escape 
any  injury. 

Nectria  Cankers,  Nectria  cinnabarina  (Tul.)  Fr.,  and  A'',  galli- 
gena  Bres.,  are  apt  to  produce  more  localized  cankers,  especially 
the  latter.  The  former,  in  our  opinion,  is  not  a  serious  trouble  as 
it  seems  to  follow  winter  injury  only,  and  is  especially  prominent 
on  those  trees  least  hardy.  The  clustered  bright-red  fruiting 
pustules  are  conspicuous  on  the  dead  bark.  '  The  latter  species 
makes  a  distinct  canker  that  slowly  enlarges  year  after  year,  in 
time  showing  a  series  of  concentric  rings  of  denuded  wood  with 
the  canker  deepest  at  the  center.  It  is  especially  prominent  on 
black  birch  in  the  woods  but  is  occasionally  found  on  cultivated 
trees  of  this  species  as  well  as  on  apple,  maple  and  oak. 

Treatment:  Treatment  of  leaf  destroying  fungi  by  spraying 
depends  upon  prevention  rather  than  cure.  Hence  the  sprayings 
must  begin  before  infection  and  continue  while  this  danger  lasts. 
This  usually  takes  from  two  to  five  treatments  according  to  the 
disease.  With  the  anthracnoses  and  leaf  curls,  these  treatments 
usually  have  to  be  started  quite  early,  in  some  cases  as  soon  as  the 
buds  begin  to  swell  in  the  spring :    with  the  leaf  spots  and  mil- 


190  CONNECTICUT   EXPERIMENT    STATION  BULLETIN    263. 

dews,  some  time  in  the  late  spring  or  summer,  before  the  first 
signs  of  injury  show.  With  rusts,  spraying  is  usually  of  little  or 
no  value.  In  deciding  whether  spraying  is  desirable,  one  must 
take  into  consideration  how  injurious  or  obnoxious  the  fungus 
has  proven,  especially  the  preceding  year,  and  how  frequently  it 
causes  trouble.  The  4-4-50  Bordeaux  mixture,  on  the  whole,  is 
the  best  fungicide  to  use ;  in  some  cases  where  conspicuous  sedi- 
ment is  objectionable,  commercial  lime  and  sulphur,  1  to  50  gal- 
lons of  water,  can  be  used.  When  necessary,  an  insecticide  can 
be  added  to  either.  See  the  Station's  Spray  Calendar  for  further 
information. 

Treatment  for  the  Blights,  Cankers,  and  Blister  Rust  is  chiefly, 
as  already  indicated,  through  pruning  off  the  invaded  parts. 
Occasionally,  under  certain  conditions,  spraying  is  also  given. 

WOOD   DESTROYING  FUNGI 

Nature:  Almost  all  of  the  wood  destroying  fungi,  whether 
on  living  or  dead  wood,  belong  with  that  class  known  as  shelf 
fungi  and  toadstools.  These  represent  the  larger  and  more  con- 
spicuous fungi.  Some  of  them  are  real  parasites  on  the  trees, 
killing  the  living  tissues  first  and  later  causing  decay  of  the  dead 
wood ;  others  are  saprophytes,  occurring  only  in  the  heartwood 
and  causing  its  deca}^  Many,  while  not  strictly  parasites,  are 
semi-parasitic  as  they  cause  some  injury  to  the  living  tissues 
though  usually  confined  to  the  dead.  Therefore,  it  is  not  always 
easy  to  distinguish  the  parasitic  from  the  saprophytic  forms.  We 
treat  them  together  here,  dealing,  however,  only  with  those 
saprophytic  forms,  that,  in  our  experience,  commonly  occur  on 
the  dead  wood  of  living  ornamental  trees.  Most  of  the  fungi  dis- 
cussed belong  to  that  group  known  as  Polypores,  so-called 
because  their  spores  are  borne  in  pores  that  form  the  lower  sur- 
face of  the  conspicuous  fruiting  bodies.  Some  have  their  spores 
borne  on  spines,  teeth,  gills,  etc.  Many  other  species  are  more 
prominent  as  agents  of  decay  in  dead  forest  trees  than  those  men- 
tioned here.  There  are  others  that  are  more  important  as  para- 
sites of  living  trees,  but  we  have  not  met  with  them  on  ornamental 
trees  in  this  state. 

Trunk  Forms:  Daedalea  qucrcina  (L)  Pers.  confines  itself 
largely  to  oaks  and  is  rarely  seen  fruiting  on  living  trees  though 
on  dead  stumps  in  the  forest  it  is  common.  It  occasionally  causes 
a  heart  rot  of  the  ornamental  oaks  even  if  rarely  fruiting  on  the 
same.  The  fruiting  body  shows  as  a  conspicuous  bracket,  light 
brown  in  color  and  of  a  semi-corky  texture.  The  lower  fruiting 
surface  has  very  large  irregular  or  labyrinthiform  pOres. 

Fomes  applanatus  (Pers.)  Wallr.,  like  all  the  species  of  the 
genus  Follies,  is  a  perennial  fungus  developing  a  new  poroid  fruit- 
ing layer  each  year  over  that  of  the  preceding  year,  so  that  when 


WOOD    DESTROYING   FUNGI  191 

cut  through  these  show  as  a  series  of  stratified  tubes.  This  species 
is  one  of  the  largest  and  most  common  of  the  shelf  fungi.  It  is 
not  found  fruiting  on  living  trees  as  commonly  as  on  the  dead 
ones.  The  woody  shelf  varies  in  size  from  a  few  inches  to  even 
a  foot  or  more  in  width,  and  projects  out  from  the  trunk  hori- 
zontally almost  as  far.  Its  upper  surface  is  a  light  brown  and 
its  fruiting  surface  is  white,  minutely  poroid  and  easily  etched; 
the  tissues  within  are  chocolate-brown.  We  have  found  it  occa- 
sionally on  living  maples,  poplars,  willows,  apples  and  peaches, 
and  believe  it  to  be  the  common  heartwood  rot  of  the  maple. 

Fames  connatus  Fr.  is  a  whitish,  semi-fleshy  or  finally  some- 
what woody,  species  less  than  a  foot  wide  and  consists  usually 
of  several  irregular  shelving  and  overlapping  brackets.  The  fruit- 
ing surface  develops  flesh-colored,  small,  thin-walled  pores  having 
a  satiny  lustre.  We  have  found  it  fruiting  on  hickory  and  hard 
maple  where  it  caused  heartwood  rot. 

Pomes  igniarms  (L.)  Gill,  is  a  single,  woody,  roundish  to  hoof- 
shaped  bracket  four  to  eight  inches  wide.  It  is  at  first  light 
brown  and  smooth  above  but  with  age  dark  brown  and  more  or  less 
concentrically  zoned  and  rimmed.  Below,  the  minutely  poroid 
surface  is  a  rusty-brown  color.  It  has  been  found  on  oaks  and 
apples,  where  it  seems  to  injure  somewhat  the  living  tissues  as 
well  as  cause  rot  of  the  wood. 

Poly  poms  sqnamosiis  (Huds.)  Fr.  is  a  semi-fleshy  mushroom- 
like fmigus  with  a  side  stem.  The  upper  surface  is  covered  with 
conspicuous  patches  of  rusty  scales  and  the  lower  is  coarsely 
poroid.  It  has  been  found  a  few  times  on  living  maples  where 
heart  rot  was  present. 

Polyporus  sulphureus  (Bull.)  Fr.  is  a  striking  species  with 
adhering  and  overlapping  brackets  of  considerable  size  that  are 
at  first  fleshy  but  on  drying  corky  in  texture.  The  upper  surface 
IS  orange-red  while  the  lower  is  a  sulphur-yellow  with  moderate 
sized  pores.  While  commonly  a  saprophyte  on  stumps  and  logs, 
at  times^  it  is  parasitic  on  living  trees  especially,  as  seen  here,  on 
oak. 

Polysiictus  conchifer  Schw.  is  a  small,  papery,  conch-like 
species  found  on  elm  limbs  where  it  produces  slow  rot  and  causes 
the  branches  to  break  off  easily  in  storms.  Some  writers  con- 
sider it  semi-parasitic. 

Pleurotis  sapidus  Kalch.,  P.  ostreatns  Jacq.,  oyster  mushroom, 
and  P.  ulmarius  Bull,  are  all  evident,  fleshy,  gill  fungi  of  the 
mushroom  type.  The  two  former  occur  as  large,  usually  clustered 
or  overlapping,  brackets  with  the  individual  parts  narrowed  back- 
ward to  a  moj-e  or  less  distinct  base  down  which  the  gills  run  for 
a  short  distance.  The  last  species  consists  of  a  single  fruiting 
body  with  a  much  more  pronounced  stem,  arising  near  the  center 
of  the  cap,  to  which  the  gills  are  attached  by  a  notch.  All  are 
white  forms  with  the  tops  often  more  or  less  brownish,  especially 


192  CONNECTICUT   EXPERIMENT    STATION  BULLETIN   263. 

toward  the  center.  They  are  most  frequently  found  on  the  elm 
and  hard  maple  and  are  associated  with  a  heart  rot  of  the  wood. 
All  three  species  are  edible. 

Hydmim  sepfentrionale  Fr.  is  a  very  conspicuous  but  rather 
uncommon,  semi-fleshy  when  young  but  leathery  when  old,  brack- 
eted form  with  the  overlapping  irregular  shelves  joined  to  the 
trunk  by  a  united  but  not  distinct  base.  The  tops  of  the  shelves 
are  whitish,  often  somewhat  scabrous  and  the  lower  fruiting  sur- 
faces are  differentiated  quite  markedly  from  other  fungi  by  the 
very  crowded,  pinkish,  fine,  fruiting  spines  about  half  an  inch  in 
length.  It  has  been  found  here,  so  far,  only  on  hard  maple  and 
hickory  and  is  apparently  semi-parasitic. 

Root  Forms :  It  is  not  always  easy  to  determine  whether  roots 
have  been  killed  by  these  larger  fungi,  since  the  fruiting  bodies 
are  not  usually  present.  Even  when  either  the  m3^celial  threads  or 
the  fruiting  bodies  are  seen  it  is  still  a  possibility  that  the  fungus 
is  a  secondary  agent  following  winter  or  some  other  injury.  The 
only  two  species  we  have  found  here  apparently  injuring  the  roots 
of  ornamental  trees  are  of  the  toadstool  t3'pe. 

Armillaria  mellea  (Vahl)  Quel,  is  the  most  important  of  the 
mushrooms  attacking  the  roots  of  living  trees.  The  umbrella-like 
cap  is  usually  a  honey-)'ellow  with  patches  of  brownish  scales ; 
the  gills  are  white  and  the  central  stem  has  a  more  or  less  evident 
ring.  They  occur  in  clusters  on  the  ground  with  the  mycelium 
forming  conspicuous,  dark  colored,  rounded  strands  running  over 
the  roots  and  flattening  out  under  the  bark  where  the  woody 
tissues  are  invaded.  It  is  more  likely  to  attack  coniferous  than 
deciduous  trees. 

Collybia  velutipes  Curt,  is  a  yellowish  to  tawny  mushroom, 
somewhat  smaller  than  the  preceding,  that  is  especially  distin- 
guished by  the  velvety  brown  stems  of  the  clustered  fruiting 
bodies.  It  is  claimed  by  some  to  cause  injury  to  the  roots  of  trees 
though  commonly  found  on  dead  wood. 

Treatment:  F'or  further  statements  concerning  the  control  of 
wood-destroying  fungi,  the  reader  is  referred  to  the  articles  by 
Collins  and  Filley  elsewhere  in  this  Report.  We  shall  mention 
here  only  the  fundamental  requirements.  The  first  is  the  com- 
plete removal  of  all  decayed  or  infected  wood  and  bark  to  prevent, 
or  at  least  to  arrest,  further  decay.  The  exposed  wood  is  usually 
given  an  antiseptic  and  waterproof  coating  or  coatings.  The 
cavity  should  be  properly  shaped  and  the  bark  so  left  that  rapid 
callus  formation  is  favored.  Whether  or  not  the  cavity  should 
be  filled  is  a  matter  of  opinion,  but,  if  filled,  there  is  no  question 
that  it  should  be  done  properly.  This  means  that  the  filling 
should  be  permanent,  semi-flexible,  waterproof,  non-injurious  to 
the  living  tissues,  especially  the  cambium  layer,  tight  fitting  or 
better  adherent  to  the  wood,  and  so  shaped  that  the  callus  readily 
grows  over  its  exposed  surface. 


PLATE  IX 


Black  oak  on  Station  grounds,  broken  by  ice  on  February  5,  1924.     A 
tree  surgeon  is  needed  in  such  a  case. 


PLATE  X 


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m 

a.  View  in  Pomfret  where  trees  were  broken  by  ice  storm  of  Novem- 
ber 27-30,  1921.  This  scene  also  justifies  the  tree  surgeon.  Photograph 
December  6,  1921. 


b.  Elm  tree  in  Mount  Carmel,  showing  bad  pruning.  Cavities  usually 
follow  such  careless  work.  All  cuts  should  be  made  close  to  the  trunk 
or  branch.     Photograph  1909. 


PLATE  XI 


a.  Young  elm  tree  in  Pomfret,  where  a  large  branch  had  been  removed 
the  preceding  year.  This  was  a  good  cut,  and  healing  is  well  started. 
Photographed  in  1909. 

b.  The  same  wound  four  years  later.     Photographed  in  1913. 


c.  Large   red   maple   in   Bridgeport   injured   by   fire.      Cavities   were 
filled  with  cement  concrete  in  sections. 

d.  Sugar  maple  near  the  preceding,  Bridgeport. 

The  work  on  both  trees  was  overdone.    The  bolts  were  so  near  together 
that  the  cambium  died  between  them. 


PLATE  XII 


a.  Elm  tree,  Stamford,  filled  with  "Nu  Wud".  Cambium  dead  at 
bottom  of  cavity.  Filling  has  since  been  replaced.  Photographed  August 
26,  1924. 

b.  Elm  tree,  Greenwich,  filled  with  "Nu  Wud".  Photographed 
August  25,  1924. 


c.  Elm  tree  at  Baltic  filled  with  cement  concrete  in  sections.     Photo- 
graphed September  13,  1919. 

d.  Elm  tree  at  Old  Lyme  injured  by  fire  and  filled  with  cement  con- 
crete not  in  sections.     Photographed  September  12,  1919. 


PLATE  XIII 


a.  Large  dotible  elm,  Westport,  where  one-half  was  broken  away  in  a 
storm.  Resulting  cavity  was  filled  with  stone  and  brick  and  covered 
with  a  layer  of  cement,  which  has  now  broken  apart.  A  home-made 
filling.    Photographed  August  26,  1924. 

b.  Elm  in  Greenwich  where  cavity  had  been  filled  with  monolithic 
cement  concrete.     Photographed  August  25,  1924. 


c.  A  satisfactory  filling  of  sectional  cement  concrete  in  oak,  Sound 
Beach.     Photographed  August  26,  1924. 

d.  Large  white  oak  at  Rye,  N.  Y.,  filled  with  sectional  cement  concrete. 
This  is  rather  unsatisfactory,  as  filling  is  broken  somewhat  and  new  tissue 
has  been  killed  at  base.     Photographed  August  25,  1924. 


PLATE  XIV 


a.  This  splitting  tree,  a  sugar  maple,  Cheshire,  has  just  been  bolted. 
Photographed  August,  1920. 

b.  Example  of  poor  cavity  work  in  a  sugar  maple,  Goodyear.     The 
filling  has  mostly  fallen  out.     Photographed  September  1.3,  1919. 


c.  Open  cavity  in  large  sycamore,  Bronx  Parkway,  N.  Y.  Unsatis- 
factory because  decay  sets  in  back  of  the  waterproof  coating.  Photograph 
August  25,  1924. 

d.  Unsatisfactory  filling  of  monolithic  cement  concrete.  This  filling 
was  put  in  over  the  bark  and  is  now  being  pushed  out  by  new  growth. 
Sugar  maple  tree  in  Hamden.     Photographed  in  1909. 


PLATE  XV 


a.  Elm  in  Wallingford  where  curious  shaped  cavities  (possibly  cankers) 
have  been  filled.     Photographed  in  1912. 

b.  Large  elm,  Stamford,  filled  with  sectional  cement  concrete.  There 
is  a  white  exudation  near  the  base  and  the  bark  has  been  killed.  Photo- 
graphed August  25,   1924. 


•'K^cHi^r* 

c.  Elm  in  New  Haven,  showing  cankers  on  the  trunk.     Photograph 
August  27,   1924. 

d.  White   pine   in    Cornwall,    struck   by   lightning,    showing   scar   on 
trunk.     Photographed  September  13,  1917. 


PLATE  XVI 


Giant  white  oak  on  farm  o£_D;^  f^.  B.  Graves,  iedyard.     This  tree  has 
survived  for  at  least  300  year?  \^t|t<)|ti  the  aijj  fl  a  tree  surgeon. 


University  of 
Connecticut 

Libraries 


ayi!3;juzoyt)4b// 


